All the symptoms of an ulcer but none found?

Last year out of nowhere I started getting diarea accompanied with bad stomach pains....This last for a week or two before I went to the doctor. I go to my doc and he first tells me to get some prilosec, he thinks its just heartburn or something eh. He has my blood taken before I leave though. Calls me later that day telling me I have pancreatitis. I get my blood drawn some more. Get a CT scan, nothing shows. Get an ultrasound, nothing shows. After about a month of pains, it goes away and my stool SLOWLY gets back to normal. Fast forward to now, its back again, its been about 8 months or so Id say.

My symptoms

-Stomach pains all day

-Especially hurts after eating

-Diarea

-Lowered appetite