What a heart-breaking situation for your daughter -- and for you.
Naturally, your little girl is angry. First, she's in pain, and that makes anyone miserable, frustrated, and ready to lash out. Second, she can't do the things she wants to do, that most children can take for granted. Fourth, her whole life is medical-ized and this illness dominates her life. Finally, she feels different from other kids, just at an age when girls especially get so worried about being accepted. This would be a lot for anyone to handle, let alone an 11 year old.
Some questions about her medication:
*Are the doctors aware that you think it causes mood swings? Anything they recommend about that?
*Does the medicine provide adequate pain relief, and if not, is there an option for you and your daughter to learn hypnosis to manage the pain? Hypnosis has no side effects, and very empowering.
How to help her deal emotionally with her illness?
1. Let her cry and scream. It IS unfair. She has every right to be upset. When she lashes out, stay with her and empathize with how upset she is. Of course don't let her hurt you, but stay as kind and calm as you can and keep an emotional bridge with your soothing voice. Under her rage is grief, for the life she has lost and will never have. That grief is huge because the loss is huge. I know it is hard to see your child grieve and rage, and part of you just wants your happy girl back. But before she can adjust, she has to accept this situation, and that means grieving. So when she's upset, your job is to accept her feelings and empathize about how mad -- and how sad-- she is.
2. Give her other outlets to deal with her grief and rage. Art is a wonderful way for children to process emotion. Encourage your daughter to "draw" her upset on days when she is grumpy. It doesn't have to look like anything to be therapeutic. Just nod and say "I see you used a lot of blue today" or "I see a lot of energy in this drawing" or "Tell me about this picture." Then listen, empathize, and hug her. You might put dates on her artwork, and put it all in a big folder or portfolio. That shows her you value the art, and see it these expressions of pain as a changing self-portrait.
3. In order to stay calm with your daughter when she is upset, it's important that you have a way to process your own pain about her situation. Journal, cry, talk to a friend or counselor to support yourself through this hard time. Your daughter has a lot of crying to do, and she needs you to have worked through your own emotions enough that you can deal with the rawness of her pain. Otherwise, it would be natural for you to find her pain unbearable and to give her the message to shut it down. But repression won't work here; she needs to express it.
4. Stay positive. Empathize with your daughter's grief and rage, but keep your expectations high. Kids who have a "poor me" attitude are cultivating a chip on their shoulder (anger) and a sense of powerlessness. That's not what you want, obviously. Instead, empathize with her pain but hold the expectation that she is a unique individual with much to contribute to the world Tell her that everyone has trials, hers just came earlier than most, and you know she is strong enough to make it through even this. So expect her to do well academically and to find other passions, such as art, music, writing, reading, etc. Expect her to be a kind and compassionate person, even if sometimes she can't be because she is just too pained or angry. Expect her to pull her weight in the family by doing chores (just like her siblings, if she has any), and find chores she can handle. (If she does have siblings, be sure to spend Special one on one time with them every day, as well as with her.)
I don't know if you are a spiritual person, but your daughter is trying to make sense of a very unfair situation. You can completely validate that, even while understanding that your daughter has unique gifts in spite of her burden, and maybe even because of her burden. If that makes sense to you, it will communicate itself to your daughter over time -- not in a way that invalidates her pain, but in a way that makes sense of it. If you are not a spiritual person, finding meaning despite the pain is much harder, but you can certainly communicate your belief that we can all lead meaningful lives that make a contribution, even those of us with a chronic illness.
5. Books are a great way to help children process emotion. Keeping A Secret: A Story About Juvenile Rheumatoid Arthritis by Elizabeth Murphy-Melas is one book about Juvenile Arthritis, but any books about kids struggling with illness, with being different, and with making friends will touch a chord and be helpful to her. Expect her to have big feelings about these books as she reads them, see it as an opportunity for a great discussion, or maybe a good cry. The more your little girl has opportunities to feel and express her big feelings, the more quickly she will get past them.
6. Play physical games with your daughter. One of the issues she is grappling with right now is that she doesn't feel physically capable. She needs an antidote to that. Wrestle with her and let her win. Let her push at you, and finally push you over. A great book that describes how to do this is Playful Parenting by Lawrence Cohen. He thinks it is important for all girls to gain a sense of their physical power, and for a child with physical issues it's imperative.
7. Your daughter needs a friend, and she needs your support to make one. Talk to the teacher. Is it true that the other girls won't play with her because she is limping? Does the teacher have any ideas about a child your daughter could become friends with? Can the teacher pair her with another girl for a special project, and you can build on that to invite the girl over to work on it, go for ice cream, etc? What does the teacher suggest?
It is painful to be different, and maybe especially so at the age of 11, so finding ways to promote friendships needs to be at the top of your family list. What happened to her friends from before her illness? Is there a club at school where she could make friends with the same interests?
8. Your daughter needs something in her life that she loves, and that makes her happy. It sounds like so far, that thing has been cheerleading. I understand why her dad feels it is too much for her, but I think it would be a mistake to pull her from it. She needs it right now. Even if she just sits on the side and learns the cheers, the bonds with the other kids are very important to her right now.
BUT she will become more and more frustrated with it, almost certainly. And at some point, she will most likely tell you she is ready to stop. Let her make that call. And if you can work with her to discover another passion, it would be very helpful to her. There are many passions that don't depend on physical strength. Your daughter is being sent in another direction. Help her learn to listen to those messages.
Jessica, I hope these suggestions are helpful. You have a lot of heavy lifting to help your daughter right now. Hang in there. Remember that sometimes our greatest tragedies are also our greatest gifts, in ways we could never have foreseen. I wish you and your family every blessing.