Bleeding. Help...

I stopped bleeding 3 weeks Postpartum. I'm 6 weeks Postpartum & I started bleeding again about 8 days ago. Had to bring out the pads again. WAYYY too much for a pantyliner. It's bright red blood with clots here & there (not huge, but maybe penny sized)... I'm a FTM so I'm not sure. I asked my cousin, she said its normal that its still lochia (I thought that was discharge, not blood). & my daughters father thinks it's my period. I wasnt sure your period could even come this early. I just had my baby 6 weeks ago. Not to mention I had sex once in my 3rd week PP & once in my 4th week PP. What is it? Did I do something wrong by having sex or something else???