I would recommend that you seek a doctors care to check everything out- I know it's scary, but not knowing doesn't make the problem go away- it will only get worse. If you seek medical care, you can come up with a plan to address your concerns and what ever the issue is- so get to a doctor and let the know what's going on. Best of luck to you and let us know how you are doing!
If its spicey food that can be severe heartburn or if fatty food it could be your gallbladder. To elviate your worries its best to see a GI doctor. A GI doctor can do tests to rule out what its not and find out what it is.
I am glad to say my issues with losing weight and severe diarrhea was C Diff or Clostridium Difficle. It is a Healthcare acquired infection. I most likely contracted either in the hospital, surgery center or doctors office. The bacteria toxins are worsened by large amounts of broad spectrum antibiotics given. Only time I had a antibiotic like that was when I had my GB surgery. I was finally diagnosed with C Diff in Oct 2015. I still have issues with bile acid diarrhea that happens after GB removal but take a strong probiotic that does lessen the times I go but keeps my stools formed and not runny. As for your symptoms I am not a medical expert but it seems like Gallbladder or Ulcertive Colitis which could give you symptoms like yours. I would see your Primary Care doctor first then if needed bevrand get refered to A GI doctor as soon as you can. Best wishes in your health.