My DS is a little more than a year out from his leukemia diagnosis. It was something I also feared because he has Ds.
I think if you are worried, you should go get her blood work done.
DS was a perfectly healthy little boy one week, the next week we were in the hospital. I felt so terrible guilty that I missed something, but talking with other parents and their journey, I learned that the type of leukemia presents very quickly.
Here is what I saw that I wondered about. Over the preceding summer he had 2 separate instances of 24 hour mystery fevers that seemed to coincide with unusually swollen mosquito bites. He also seemed a little weak during that time, and did not want to walk too much. I dismissed these things at the time, but they did nag in the back of my head a little. I though maybe he was fighting a mosquito born virus, and he has low tone, was new to walking, and very cautious, so not wanting to walk was a reaction to not feeling great.
The week before he was diagnosed he was irritable at night, no fever. I thought maybe he was getting an ear infection (neither one of my kids had ever had one before.) We treated him for the ear infection with herbal remedies, he rallied and seemed to recover in 24 hours. During the 2 or 3 days we suspected an ear infection, one evening he alarmed me by looking a little pale, I thought he was going to throw up. It passed within a minute or two. He had a low grade fever that night. I think that was Wednesday night.
We do not usually go to the doc for illness, unless something unusual happens, I remember looking up the doc's weekend hours Friday night thinking I might need to take him in, just because instinct was pinging at me.
Saturday he was really good. Then that night he got a fever again, did not want to walk, was very clingy.
Sunday morning I opened my eyes, DS was sleeping in his bed right next to me, and with out being fully awake I sprung out of bed, shouting to DH we were going in to the doc, got dressed and went. I have no idea what triggered the panic feeling, I just reacted.
While we sat in the docs office I held DS, so I was not watching his face. After about 45 minutes of waiting, the nurse came out to call in a patient, looked over at DS and FREAKED OUT! Evidently he was very pale. They rushed us in and did a toe prick to check his iron, it was a 3, and I just knew. We were in an ambulance and on the way to the children's hospital 5 minutes later.
Once at the hospital, DS was given blood, a smear was done, and we knew it was most likely leukemia. He started treatment that day, was in remission 30 days later, and you would never know anything was wrong to look at him today. He still has 2 years to go with chemo, but the fear, for the most part, has left me and i feel confident he will live a long and healthy life.
I won't sugar coat, that 30 days was hell. After a few days in hospital, he needed to spend a week in PICU, sedated, on a resporator, being treated for congestive heart failure (due to his body compensating for the lack of blood he was making). He had several procedures in the OR, 2 bone marrow draws, his port being placed. He had several blood transfusions. The first 30 days of chemo is intense, the steroids in particular (I understand that all kids with cancer go through a similar 30 days.) He was in pain from the leukemia, it crowds the bone marrow, so he was on some strong drugs to manage that.
Looking back, a lot of the hell was the fear he would die. The fear of all the new procedures. Just the reality of processing what was happening. I was terrified of all of the drugs. He was unconscious for the worst of it (thank goodness for small favors.) Each individual procedure was in itself, not too bad. He was sedated for the big stuff, I don't think he even knew they happened. He was prenumbed for the very few needle pricks, and the morphine controlled his pain very well. He tolerated the chemo well, except for the steroids, which make everyone that takes them cranky and puffy looking.
I think you should follow your instincts. If you suspect something is off, go get it checked out. If you need to talk some more, feel free to message me, or we can talk here.
I am wishing you the best of luck that everything is fine, and you never have to go through this with your daughter. Cancer sucks. But know this, in the last 5 years, things have advanced in amazing ways, DS was given a 97% chance of survival, something that just was not possible in the recent past.