I have always had IBS but for the past several months since July I've had bouts of diarrhea that last a week or two. It is taking over my life. I ended up in the hospital for a while before. They think it's post infectiou. So I tried lomotil a couple weeks ago and it worked like a charm. But then it started to lower in it's effectiveness so i took more, and now it has stopped working and i'm back to being bad again. Why did this happen and will it work again? I'm also taking rifaxamin could that be it