My suggestion is to try the anti depressants as they help to slow the bowel.
Goodluck
I'm dealing with the same issue. Take probiotic daily, 6 bill. strains, activated charcoal when the bloat is bad, fennel capsules etc. etc. Yes, some foods make it worse but I did the elimination diet and came up with only a FEW food items that don't cause flare up or symptoms. I'm also depressed and anxious because it's so painfull and you never know when an attack will strike!
Elimination diets also help to discover which foods are aggravating the IBS. Probiotics and elimination diets can really help a great deal with IBS. SSRI's are often prescribed because stress aggravates IBS, so does depression. And, seratonin plays a role in bowel health. Although, in my case the dietary changes and the addition of probiotics made more difference than any SSRI ever did.
http://www.whfoods.com/genpage.php?tname=faq&dbid=30
I would try a probotic, You can buy it over the counter at the drug store and it contains 10-35 billion Good bacteria (Lactobacillus Acidophilus) It works wonders. Try it if you havent and you should see a difference. It worked for me and I had a issue some what like yours.
For your issue try the 35 Billion type, I seen it a Meijer store but all drug stores should have it as well