Period problems

Faith

My periods have always been normal, in may of last year I got pregnant with my son and he was born in February. Periods were still normal after he was born, up until this month. I had my period the 4th-8th of this month and my boyfriend and I had sex tonight and when we were done, we noticed that I was apparently bleeding and didn’t know it. No cramps, bloating or any of my regular period symptoms. No pain whatsoever. Is this normal? Or should I call my doctor?