Lower abdominal pain & sex

Me and my boyfriend have been ttc for over 8 months. Last night we had sex and the whole time I had a weird dicomfort in my stomach, not like pain but just and uncomfortable feeling that I've never delt with and was curious if anyone else had felt with something like it. It hurt worse after sex and then just slowly went away after like 5-10 minutes. I'm also a couple days late for my period and got a cold or something like a day or two ago. Of anyone has any advice to feel shy and please tell me your experience?