Welcome, Rebound!
Irritable bowel, anxiety, bipolar... that's me. It took a Iong time to get a diagnosis, a gastroscopy and an endoscopy - not fun - before my doctor basically said "You've got irritable bowel and there's nothing I can do about it." I cried when he said it, I was so hoping they could just figure out what was wrong and the FIX IT. But nothing ever seems to be that simple. I know exactly what you are talking about, so you're not alone on this. It took me a long time to figure out that the irritable bowel was related to my anxiety. And the catch 22 is that I'd be so nervous that I was going to get sick that I WOULD get sick, because I was nervous about getting sick from nervousness... It went on and on. I hated camping with friends because there were no bathrooms and I didn't want everyone to know. I hated car trips, days away with friends, going out to crowded places, the theater, parties where people would be waiting outside the bathroom door... I was always horribly ill before and during piano recitals and would have to go to the washroom many times during them. Anywhere it would be difficult to get to a nice private bathroom, I'd stay away. At one point I was so SICK OF BEING SICK I refused to eat and had nothing but water for four days. Incredibly, symptoms continued... I'm sure you know what those are, I don't really feel like writing about that specifically in a public forum (eew). I understand now that stress, wearing clothing that is too tight on the abdomen, not getting enough sleep, and not eating enough will make me sick. It doesn't seem to matter much what I eat. I tried food journals, and even went on a no carb no milk diet for five months, eating mostly dried fruit, and I felt better for a while but was still getting sick so I gave up. As long as I stay away from a lot of sugar and junk food, or I will inevitable get sick the day after. If I get in a fight, feel nervous about a party or date, or see a certain X of mine, I will immediately feel ill and have to run to the bathroom. I try to avoid all the triggers, I have been a lot better since the anxiety improved, but part of the reason for that is I was drinking to self medicate for anxiety, which was a vicious cylce again because drinking would make me sick too... it's so frustrating.
The best I can tell you would be to try to get professional and/or medical treatement for the anxiety, which can be caused by bipolar, focus on positive social experience, and when you stop being nervous or at least learn how to deal with it, you'll hopefully stop being sick too.
I'm not absolutely sure but I think this is caled a psycho-somatic reaction illness? Something that happens to your body because of what's happening in your mind. Like I said, I didn't put two and two together on that one for a long time, but I get it now. Talk to your doctor, and keep posting.