At time like this, I usually drink a huge glass of cold water, and listen to classic music, and lay in bed try to sleep. Or I will read a book/watch anime, so i can focus on something, and not thinking about what is going on, until my brain is tired from watching too much, i'll end up sleeping. IDK but after sleep, i feel so much better. (That probably just me, but hey, ^^)
Don't let your depression undo all your hard work. Things will turn worse if you do so becuz then you have to deal with another depression from unable to keep your weight off >.<" If you live near a park or somewhere close to nature, take a long walk and breath fresh air there. It might help too.
Hope you feel better soon