I too have had IBS for a few years and I'm lactose intolerant as well. My stomach has always been in contention with me. I went to the doctor, I tried suppositories, enemas, and even prescribed vitamins and multi-vitamins. None of it worked. I can however, give you a little bit of hope. I switched to a really good probiotic, Active Digestion Enzymes, from a company called Global Health Trax as well as I now take Active Systemic Enzymes. These two products of theirs are pretty cheap actually, no more than most multi-vitamins and they really really rock! I seriously suggest looking into them.
-savannahshealth