Period off after he nutted in me....

Ugh so this has really been bothering me ever since it happened but my now ex boyfriend nutted in me last month and I didn’t take a plan b or anything and It was 3 days before I ovulated..... so after that 4 days before my period was supposed to come I started light bleeding (I had a strong feeling it was implantation bleeding but then said nvm bc of the length and hearing other people’s input) anywhooooo it was a really off period and on top of that I started to have a decreased appetite (took pregnancy test and it came back negative) fast forward to this month I started my period on Christmas and today I have little to no period.... it’s very light.... can someone explain whats going on? I don’t want to take another pregnancy test bc i don’t want to get my hopes up. My period is usually 5 days and is medium to heavy flow with little to no cramps.... I really need some kind of explanation (I don’t take meds)