Had sex, got my period 2.5 weeks early

So I had sex for the first time ever (last week) about a week after I got my period this month I'm not currently on birth control but yesterday I got my period and it was super weird because I got it way early and at night which never happens because my cycle is pretty regular and I always get my period in the morning. It was also super light spotting but then today I woke up to a blood bath which again was very different for me.

I'm just wondering if this is normal? I'm not sure why sex would throw my period off but I'm just surprised it came out of nowhere.