700-900 calories per day is making me feel sick? Help?

Currently, I'm eating between 700-900 calories per day,I'm 5'3", 114 pounds, size 0-2. A few months ago I was at 105 pounds, eating 400 per day, and I know that i was starving then, but am I starving now? I feel like 900 is too much, i feel full/sick all the time and it's pretty unpleasant. I eat very healthy food, fruits and veggies mainly.