Bleeding after period ended.

Keah
I started my period on 3/17 and it lasted until 3/22. Today is 3/27 and I am bleeding again. My husband and I have had sex a few times within the four days that I wasn't bleeding. This has never happened to me. I am not on the pill and we do not use protection. Has anyon experienced this? If so, what was te problem? Should I be worried?