birth control and unprotected sex

Question!!
So I've been on birth control for about a year but had a 2 month break & have been back on it for 3 and a half months. Yesterday I had unprotected sex and he came in me and I'm wondering if I should take plan b. My period ended 2 days ago and I started back the pill on Thursday, but the pack before, I was a little inconsistant (never take at the same time, and I missed a day). Should I get plan b or should I be okay 😩😩 I'm 20 and still not use to birth control info