Bleeding for 2 Weeks? Please comment!

So i had my period starting Jan. 18 and it ended (i thought) the 23. My boyfriend and I had sex and he said you're still bleeding which was odd but i just shook it off to be nothing. But i've been bleeding red blood and some days brown blood. It's just very unusual for me. I also have been pretty tired lately. Can someone help me out as to why i would bleed for 2 weeks?