Just going to be straight with my opinion and you can take it how you will. Ask to get a colonoscopy. Not because I think you have it, because I was in the same situation as you. I mean, either borderline diarrhea or soft stool every single day for months. After a few months, I went the the Dr and she wasn't concerned based on my symptoms (no blood). So I went on antidepressants. That was good for about 9 months, and I decided to go off of them (cause they also gave me diarrhea, go figure) but the meds numbed the fear and pushed them more to the back of my mind. And as soon as I went off of them, bam, fear came back just as bad. Same symptoms with the poo. So finally had the test just to assuage me. It was clear.
One other thing, it will make the HA coping a bit easier. It did for me. I still have HA and still fight it. But I went thorough one test, I was fine after I had though I was surely dying. So in your mind there's more of a chance you'll be fine again once your next "illness" comes along. Make sense?
Good luck in whatever your choice is.