2 week window

Kember
So I'm on the deep shot and in 2 weeks I'm supposed to go get my next  shot. When I first got my shot they said no sex 2 weeks befor I get my shot And they also told me to not have sex 2 weeks after I got the shot because it was easier to get pregnant. I had sex early yesterday morning and he wasn't protected so should I get a plan b pill just in case or do you think I have nothing to worry about. Or does the 2 week thing no even matter??