IBS and need to eat more often?

I think I might have IBS. I wake up every morning with a very urgent need to go. I sometimes pass long strings of mucus. When I'm stressed I go several times daily. I get gas pains so bad sometimes I can't move, and I belch all day long. One other symptom I have is that I have to eat every two hours or so even though food doesn't really sound good. Could this be because I'm not absorbing nutrients? I also get tired and lightheaded a lot.

I take probiotics and digestive enzymes... what else can I do?