I have to disagree with billp on the number of calories. 900 calories is not enough, true. But I don't think you'll starve on it, not yet, and it's certainly better than what you're doing now. The reason I asked about 900 is that I think it would help you if you had a constant
number of calories a day, even if it's low. You're yo-yo-ing between 0 and 2000 and it's confusing the hell out of your body. Get used to eating a little and you can worry about ramping up later. IMO, it's more important that you don't freak out and have the bad thoughts that you had the other night.
[To be honest, I'm not sure about 2000 . On a normal (wheat) diet, I lived on 1200 a day. On Primal I think I'm closer to 1500, but I don't keep track. At your height you need a little more, but 2000 might be a wee bit too much, especially now.]