I Have IBS With Constipation, But Lately It Has Been

I have IBS with constipation, but lately it has been very different, when it decided to, as I put it kick in, I use to just have a day of going to the bathroom all day and very painful stomach cramping. But lately it can start out that way but then can go to diarrhea along with at times getting sick and vomiting. Also I have been getting sick a lot the past few months with flu type symptoms. I have lost over 20 lbs but yet my stomach it bigger then it was before, so even tho I weigh less I look even bigger.