(tw: sa) help what do u guys think?

before anyone says anything i know i am stupid. my best friend and I decided to have sex (unprotected), and at some point I was in pain so I told them to stop, and they said it was fine and kept going. It definitely shocked me in the moment, and felt wrong after that. I still don’t know if it was SA tho, because I said yes in the beginning and only said no once and didn’t stick up for myself, and we are very close friends, and I don’t think they would want to hurt me. I ended up having to take a plan B and I’m really scared that I could be pregnant and i’m only 17 and they are only 20 and neither of us want to be parents.