
You sound *really* burnt out and that's not good for anyone.
I don't know if this will make you feel better, but you are at a REALLY hard time for nursing. It's funny how you said that she nurses like a newborn, because with a toddler I always think, "Yeah, they nurse just like a newborn if you have a 25 lb newborn who likes to claw and bite while pretending to be a gymnast while nursing!"
From my experience (nursing and knowing people who nurse) there is a time midway through the 2nd year that is just... hard. Not great sleep. Inconsiderate. Lots of gyrations. Very demanding. Then, somewhere around 22, 23, 24, 25 months it just become... easier. Not necessarily easier, but you see a lot more moms saying, "Wow, is she weaning" or "DS is suddenly sleeping through the night." I think it's because at 17, 18, 19 months they are really ramping up for a huge language explosion AND a big independence explosion. Their brain is changing so very quickly, they are really starting to understand things and they just go haywire for a little while.
That said, 17 months IS old enough to start learning some basic nursing manners. One thing that I found helpful was a tighter hold. So, instead of letting DD flop as much try getting her into a true snug cradle hold. Different things work for different people. When my kids were really trying to tweak the other nipple I would nurse lying on my side and only let them have the top side (so the other nipple was tucked under me). If you're having lots of problems with kicking, try to get into a position where their legs are more contained. Try to get their face more towards you (don't let them get in a cradle hold and then flop on their back--- that pulls your nipple AND encourages them to kick at the same time).
It also sounds like you need a little more "me" time. Even time alone to take a bath or read a book can make a huge difference. Are you eating well? Drinking enough? Can you take a walk or talk to a friend?
My suggestion for now (beyond wait it out, which is, unfortunately, the only foolproof suggestion for this issue) is what it always is: make a list of the things that bother you the most or that you most want to change and then brainstorm ways to fix them. A lot of times nursing gets blamed and then when you really look at it it's not so much a *nursing* issue, but something that is happening around nursing (like a lack of time to yourself, lack of bodily integrity, etc...).
Good luck

I know it probably won't help right now, but I have an 8 & 11 year old and I would give a *lot* to get to go back and have even one more pretty hellish day with the sweet babies they were.