I Started My Cycle Four Days Ago But On The

I started my cycle four days ago but on the other three days their wasn't blood on my pads or toilet paper when me and my partner have sex that's when the blood comes out of me then stops yes we have Unprotected sex for almost five months but nothing happened my period always comes on the same day but this period is different I always go to seven days I'm on my fourth day and no blood on Sunday we didn't have sex and that's when I got my period but we started having sex on my period Monday and Tuesday but there was blood but then would stop we haven't had sex in two days and my period hasn't came back I was on my period only for a day then it stop I'm only twenty one years old