I'm 13 and may be pregnant

hi! this is my first post here.. well.. here goes.. I've been with my boyfriend who's 15 for a while now, he's had no bad intentions, always wanted to make sure if I was okay before doing anything etc etc. I ended up having unprotected sex with him and while he didn't finish inside of me, he did ejaculate before going inside of me. We're worried that his pre-cum might have pushed some sperm that was stuck in the urethra from the first time he ejaculated. He didn't use the restroom before hand either, he took my virginity right after he finished the first time. I've been feeling really fatigued, dizzy, I've had headaches and cramping.. I haven't missed a period yet because we had sex a few days ago but my periods are always late. His mother is extremely Christian and bipolar, and I would have to move in with my dad if my grandparents knew. I'm really scared. TL;DR - Boyfriend and I had unprotected sex after he came and we're worried the pre cum could have made me pregnant.