Pregnancy Scare

So about a week ago I had unprotected sex w my boyfriend. He did not cum in me but it felt like he got some on the outside. I’m not on birth control and i don’t know which part of my cycle I’m in bc my period has been out out of wack. Like I got it for early then it only lasted two days then i got it again a couple weeks later for three days. This was a few days after my period. I didn’t get plan b should i be worried?