please help 😩

Okay so me and my boyfriend had sex two weeks before my period then a couple days before, I got my period from the 15th-20th (the last day of my period is usually just discharge) and everything was normal, we had sex last night (21st)  and on after the second round he went to go take off the condom and put water in it to make sure it didn't break and he noticed blood. Bright red blood. We called someone close and they said it could have been old blood from my period stuck in my cervix. This morning (22nd) I woke up at 3 AM and I felt a little nauseous with a tingling feeling around my belly button and a just a tiny bit lower. I fell back asleep and I woke up with same feeling a little more dull. I know I can't  be getting pregnancy symptoms from last night, but before that is what I'm worried about. We used a condom all times we did have sex. I don't know if this feeling in my stomach is a coincidence or ... idk please reinsure me lol 😩