I used the pull out method yesterday and...

Yesterday, my boyfriend and I used the pullout method when we had sex. I haven't used this method in quite a while and I was at 22% risk for pregnancy yesterday. Just now, I went to the bathroom because I felt really wet, but I thought it might be a lot of discharge. It was blood. I don't expect my period until the 30th. If my cycle has changed and my period happens to be early, it still doesn't make sense that it's so heavy on the first day, when it's usually light on the first day. I'm not sure if it's implantation bleeding either because it takes at least three days to get pregnant, right? I hope it's not. Maybe it's spotting, but why is it so heavy? Or maybe he did something up there that's affecting me today. Could someone give me some answers?