ME and my boyfriend had unprotected sex, I was on my second day of my period and as usual, heavy but on time. Now, day after sex I'm not on my period anymore, should I be worried?

Probably not, but pregnancy can happen from sex during a period if you happen to ovulate outside the norm. Some women do find that having sex during their period alters it slightly so see what happens over the next several days. To know if you do become pregnant from the recent sex, you will have to wait until your next period would be due and see what happens.

Keep in mind that no time is guaranteed100% safe. Some times in your cycle are just more likely for pregnancy to occur than others.