i keep bleeding..

I had sex a day after ovulation.. I got what I thought was my period but it lasted way longer than normal.. i’m 3-4 days it lasted 6-7.. but the last two days were light. I wasn’t bleeding yesterday and today I go to the restroom and i’m seeing blood again.. i’m so confused on what’s going in this never happened to me ever since i’ve started my period.. any clue what this is?? i’m not in any type of birth control so it can’t be break through bleeding.. i’m terrified