Possibly pregnant, bleeding after being fingered

Me and my boyfriend had unprotected sex while I was on the second day of my period. He did not ejaculate inside of me, but pre-cum is worrying me about possibly being pregnant. My period isn't due for another week, so I cannot test yet. It is 3 weeks after we had unprotected sex, and I'm worried about an incident that happened yesterday as well...My boyfriend fingered me, and I bled immediately after. It was bright red blood with blood clots, and faded into a brown discharge (still with some blood clots). The bleeding lasted for only a few hours. I'm wondering if this could be a miscarriage or implantation bleeding? I doubt it's implantation bleeding, because it would be very odd that right after I got fingered I had implantation bleeding. I'm thinking it was a miscarriage because I had lower back pains and cramps the days prior to the bleeding (also, I've been very stressed). Please tell me if a.) you think I'm pregnant and b.) if the bleeding was implantation bleeding or a miscarriage, or even something else? HELP! :'(