Is there something wrong with my body?

A while back my ex boyfriend and I did the deed but he did not cum inside of me. This was back in November. Ever since I have not had my period and every pregnancy test I took came out as negative. I don’t know what this means but I don’t feel pregnant I don’t have symptoms I just wonder what the heck is wrong with my period because im going on 57 days late and I took a pregnancy test last week and it came out as negative... any idea as to what is wrong..?