Need motivation

Ever since my pregnancy I've been having trouble losing weight I'll lose it then gain it back and I'm so sick of this cycle. I feel like I will never be able to do it without going back to my old ways when suffering from my eating disorder. Also being a single mom and trying to make it through nursing school isn't helping either. I have no time to exercise between taking care of my daughter and struggling to study and getting enough sleep also. I need to lose like 50lbs just to get to like a healthy weight.