Period Issue

Paige
I started my period on 3/8 and it didn't end until 3/14 which is unusual, considering my periods usually only last 4 days. But and my husband had sex once I was finished, then all of a sudden I started bleeding again today. It's not a lot of bleeding, but enough for a "light" tampon. The blood is also a lot darker than normal. Anybody had this happen before? My periods are like clockwork so this is very weird for me. Also a little worried how it will effect us ttc. :(