Undiagnosed issue

In 2007 When i was 17 i weighed about 130 lbs. between june- august of that year i went down to 95lbs for no reason. The doctors said you have some stomach bug. After about 4 months i started gaining a little back but never got over 120. then i started loosing weight again. I had severe upper and lower abdominal pain and diariha. My gallbladder was taken out in 09 to fix it i did not have gallstones. That didnt work. I have continued to have all the same symptoms as before but now they're more constant. I used to have attacks from 1 hour - a couple days and then relief for a while. now i can barely eat most foods. I have to plan where im going to be anywhere from 1-12 hours incase i need to use a bathroom and have problems going sometimes.
I've had 2 upper endoscopes and going in for a third, 1 colonoscopy, a few CT scans and ultrasounds. and the doctor say they dont know anything it could be. I have done many diets. Glutten Free, dairy free, high fiber, bran, no caffeen. One doctor told me to eat only chicken and carrots for a few weeks. Not one of these has given me any releif.  Once they considered it was IBS but it just seems so much worse and i havent reponded to any of the meds i've been given.
Just looking for some more ideas of what it could be. I dont drink/smoke. I wasnt stressed out before and only have developed stress from the problems ive had with my stomach. I thought maybe chrones but the doctor doesnt think so because the colonoscopy from 3 years ago didnt show anything.

[ggreg]

Well, other than some major problem with your digestive tract, I can suggest that medications will sometimes do this to a person.  If you started taking any medicine just before you had diarrhea in 2008-09, then review side effects.  I was taking a couple mental health type drugs and wound up with diarrhea numerous times a day for six months, no one knew what it was.  As soon as I went off those medicines, my diarrhea went away.

Also, if you are still trying to diet, I would like to suggest you stop doing that for a few months, drink a big glass of water before each meal (so you'll eat less and it's also good for digestion), quit eating just before you feel full, and continue to get regular exercise, so your weight won't go up.  And to keep it from going down, be sure to eat enough of all the food groups:  protein, milk and egg products, vegies and fruit, and carbs/fiber foods.  Fiber foods should be added gradually, and include oat cereal, whole wheat bread, fresh or frozen cooked vegies, fruit just for snacks, and salads.  

One thing that helps digestion is to introduce "probiotics" to what you eat, which are in Acidophilus milk or Activia yogurt from the grocery store.  Just a couple weeks of that helps.  Also, one thing that causes pain in the gut is gas, and so an ordinary Alka Seltzer Original is great for releasing that when you get that sharp pain.  Gas can come from skipping meals or eating too fast, eating fruit with a meal intstead of by itself as a snack, drinking non-brandname sodas (of all things, but they can tear up a gut), and of course bacteria in the intestines.  Your doc should draw blood and do a stool sample to check on that.

[jgskiver]

I only did the diets the doctors put me on and i wasnt taking medications before. I have tried probiotics and i dont drink caffine.