Sex during cycle make it shorter?

I've had my period for 11 years. Always lasted 7-10 days, every two-three weeks. However, this time, it lasted three days. Now, I was brave, as was my boyfriend, to get intimate in the second day (no pullout). The fourth day, I had no period. Same for the fifth. Thought it was the usual one day off. We had sex again the fourth and fifth days (no pullout). But, I haven't had anything. Is is because of the sex?