I'm 17 and can't figure out what's wrong with my stomach

Ok... Well i have been diagnosed with Generalized anxiety and it has sort of made me a hypochondriac, but this particular problem could not be made up. My family has history of having IBS and my mom has it so the doctor thinks i may suffer from it also. But my whole life i have had normal bowel movements (with the occasional contipation) but for about a two weeks now i have been (what i think is constipated) with release of very very little amounts of stool and sometimes with mucus. I don't feel sick or unusual, but my bowel movements are causing some serious worries for me. I have had extensive blood work and been tested for thyroid complication, H Pylori and lots more and have been diagnosed with gastritis a couple times. I have all the gas in the world and when i feel the urge to use the bathroom it is almost all just releasing gas. I don't know if this is from anxiety or IBS, but i am desperate for answers because i worry nonstop of having a serious stomach or intestinal problem. Please Help...Thanks