Implantation bleeding?

So. I just finished a normal period. I had sex 2 days ago and last night, last night the condom ripped and when he pulled out, some cum got on my vagina on accident. I'm in my fertile week, and about 24 hours later I got very light bleeding from my vagina that resembles implantation bleeding. Is it possible? I know it says it takes 6-12 days after fertilization but I'm so unsure, it looked exactly like implantation bleeding. I'm sorry if this sounds idiotic, I'm just very scared to be pregnant right now, I'm not ready yet. If it's not implantation bleeding, what is it? He and I didn't have rough sex nor did he finger me or do anything rough to me. Please help me I'm very worried. I'm sorry this is all over the place.