My doctor told me I had IBS too, but she never really explained it to me. I have experienced this nauseous feeling for almost two years. I do experience constipation all the time, and I think that plays a big part. I eat fiber cereal every night, but if I miss one night, I can't go the bathroom for two days. It is awful because I never really feel like I finish going to the bathroom. I feel sick after I try to go to the bathroom and then it lasts ALL day. I mean, I had real bad allergies, but now I use Flonase and that helps. I take the birth control pill, but I take a low dose so I don't think it's that. I'm just so tired of feeling like this everyday.