Random stabbing pains in abdomen?

Okay as the title says I've been having bad stabbing pains in my lower abdomen (left and right) for almost a year now. I'm 17, female, 5'3 and about 140lbs. I've been to the doctor and ER multiple times, gotten CT scans, ultrasounds, and x-rays but nothing shows. They've ruled out appendicitis and it's not menstrual cramps as I haven't even had a cycle for many months (8-9 to be exact.) There's no chance I'm pregnant and they also ruled out that it's nothing to do with my stomach or colon either. Everyone I've gone to doesn't think that it's an issue with my medication (I take Effexor, birth control that starts with an A and has iron supplements, and claritin for allergies.) This pain gets so bad that I will collapse and am unable to breathe when it attacks, normally fainting when it happens and waking back up in extreme pain. Quite a few times I've also thrown up from this and as I said have had to go to the Emergency room for it. There's another thing that happens just all the time, not just during these attacks, but every time I eat anything I get extremely sick and have an allergic reaction of some sort. I've gotten throughly allergy tested and absolutely nothing came back. I'm not sure if this is related to the other symptom but I figured I'd mention it incase it helps at all. Anyway I'm just looking for what someone else's opinion or theory is on this as so many doctors have not been able to figure it out.