It sounds like what I get sometimes. It could be a spasm, or it could be a feeling of urgency from everything being oversensitive, which is a lovely side effect from IBS. Yuck. If you do have gas, maybe it's from dairy or foods with too much fibre?
Try sipping peppermint tea slowly as this may help with spasms or wind. Get tested by a gastroenterologist if you're worried, because it can be many things. I hope this helps!