What disease do you think I have ?

I had an u/s during pregnancy and they saw small gallstones. I also always have gastric pain and food poisoning as in diarrhea from time to time, usually lasts for weeks and i cant seem to eat anything thats spicy at all...my stomach seems to be sensitive. I went to doctors they cant seem to identify the exact problem and tell me to watch what I eat....I get gastric pain and diarrhea quite often and Im convince i have some underlying problem...when I eat I never 'feel' that i'm full....what do you think it is, is it some kind of IBS or just stress.....