They say to give probiotics a while for things to improve. I'm not sure which one you've started, perhaps you need to ease into it by using yogurt or something lighter for a bit and then going ot the pills. Also, some folks do better on one type than another.
I'm not dx'd with IBS so I don't want to give advice on what to eat, but, maybe a little EVOO will help get things moving. EVOO also has some antiviral and other benefits, so maybe a TBSP after/with a light meal? You could also try a Magnesium supplement, a side effect is D if you have too much, but-- I woudn't over do it, or take it now, but perhaps try it when you are feeling better and see if it keeps things regular from there on out?