SORRY IT'S KINDA LONG.

Before I start explaining, I'm going to give the best backround information I can so this all makes sense and for some one to help explain to me what could possibly be going on.

I'm 15 and I'm not a virgin. I lost it at 14 with a guy who I thought cared about me but I was wrong and I have remained abstinent ever since. I have a new boyfriend now who doesn't force me to do anything now. We hung out the week after my period and we almost had sex, but I didn't want to so that was the end of that, no complaining that was it. He put he penis close to my vaginal opening but barely touched me but I quickly told him no and pushed his penis away from my knowledge of precum and how it's possible but very unlikely to become pregnant from it, but I was NOT gonna take any chances. He didn't ejaculate before this. Then on that Friday I was going on a trip to see my family with my older sister, just the both of us. We ended up getting in a very bad car accident. Our car flipped across the highway about 4-5 times over the medium and onto the neighbouring highway over the guardrail, our car was totalled. I escaped with contusions on my lower abdomens and my sister lucky didn't die she escaped with a broken arm and finger. When I was in the hospital they asked me if I could be pregnant and I said no but they took a urine test but then later on she came back and took me to x-rays. A couple of weeks after that I was expecting my period and it didn't come. I got worried and took one pregnancy test and it came out negative, then a week later I took another one and it was negative as well. So I couldn't be pregnant. I didn't have any symptoms of pregnancy at all and still don't. I'm now at the 3 month mark with out no period. Yesterday I had brown discharge and now today I'm having a little bit of blood. Is this my period starting up again? This can't be implantation blood. I have a OBGYN appointment on tuesday to figure this out but I want someone's knowledge and experience. I again want to apologize for this being so long. Thank you! I would really appreciate the help! :)