It could be any number of factors... I find if I spend less time trying to figure my IBS out and more time managing my symptoms.. I seem to do better. (After all the best GI experts can't figure IBS out.. so realistically I have zero chance of figuring it out myself, right?)It is good that the Mebeverine is working for you. Use imodium (a 1/2 or even a 1/4 tab if that is all you think you need) with meals or before going out may help rebuild your confidence. It could simply be a flare up and may calm down again on it's own.