what's going on?

In December my boyfriend and I were messing around in bed, long story short we did NOT have sex by my vagina was exposed to his precum most likely, anyway about a week and a half later I got my period while I had the flu and it was super heavy the first two days and it stoped the third day all together and then the fourth day just brown blood was there, no I haven't had any sexual activity since that last time and my period is two days late  and I've had all my normal period symptoms but what worries me is that I've been so tired and sleepy and of course bc of this my anxiety is through the roof. Has anyone else gone though this???