Don't know what to do 😫

My poor baby and I have thrush. Dr prescribed Nystatin. We've been giving way less than the full dose because that made her vomit terribly. The smaller doses are still causing her to be really fussy/gassy and to spit up a little after every meal. 
We've hardly had any sleep. Before the meds she would wake up, nurse, get changed and go right back to sleep at night. Now she's up for 2 hours each time squirming, on and off nursing, tugging at my already painful nipples and crying, The medicine seems to be working for her but I really don't want to keep giving it, and seems to have irritated my nipples even more. I think I've been crying more than her, I feel so awful for my tiny 2 week old! 
Wish I knew what to do :(