Pain when try to eat/drink
 

To keep thing short i havnt really been eating for coming upto about 3 weeks, i have been eating small bits and pieces to keep energy going but very small amounts (however about a week ago i started eating then purging a few tins of things at night but have stopped that for about 4 days ago). But for about the last 2 days almost everytime i try to drink or even have like a few teaspoons of something i get these horrible sharpish pains in my stomach sorta behind my lower ribs, it feels almost like indigestion i think but arent entirely sure, it happens even when i chew gum and im sorter worried about what may have caused this, couls it be an ulcer from purging? or just my body freaking out over food etc?