I've been on the birth control pill for 4 months now and take it at the same time every day. Last night my partner and I had sex and he finished inside and we've never done that before. This morning I woke up and had diarrhea but that has gone away. I'm also feeling bloated and a little bit of side pain. I'm not due to get my period for another 2 weeks. I'm worried that I could be pregnant and am wondering if I should take plan b?