Discomfort when fingered

I've started being sexually active only recently (in my 20s - only oral).

I've never orgasme because after a while we are at it I feel a bit of discomfort in my lower belly and kind of like I need to pee *and* poop... even if I just went to the bathroom right before we started messing around!!

Has this ever happened to you? I don't really know how to react in these situations if not asking him to stop :(

Thank you for your help ladies x