Period Help???

I had sex on the 19th. Rough sex, and the day after my period started. I was about 2 to 3 days until the start of my normal period so I thought nothing of it. Now, today, the 23rd, I'm not bleeding. I bled the day of sex and the day after sex, nothing since then. He pulled out and I'm on birth control, so I'm not worried about pregnancy. I'm just confused. Is this my period? If it isn't, why did I bleed? It's not the first time this has happened, but the bleeding usually stops the day of sex. If anyone has any insight, I'd be thankful to hear it! Thanks ladies ❤