unprotected sex on last day of period?

I had unprotected sex yesterday for a minute and then he put on a condom, so he didn't finish in me or anything.  it was the last day of my period, cycle day 5, and it was VERY light as usual. but today I'm cramping on mainly my right side but also both? I don't think is usually cramp on the day after my period? so should I be concerned?