I don’t think it is an allergy. (this is from someone who just went through a big series of allergy tests both scratch tests and blood allergy tests)
But I do think your gallbladder is acting up. (I had mine taken out about 1 year ago)
Get the gallbladder checked out.
You might want to check out HealthBoards and ask people there. Check the “Digestive Disorders” area primarily. There is also “Bowel Disorders” and “Acid Reflux” of the same general variety of problems.
http://www.healthboards.com/boards/index.php