Late period

ALRIGHT guys I need help..

So from the beginning, my boyfriend and I had sex when my period was 2 days late, then while in the middle of sex I started bleeding A LOT so I’m like oh ok my period is here..WRONG. It lasted maybe a couple hours then went away and never came back. I am not 22 days late on my period. Does anyone know what this means? Yes I took a test it was negative.