Help me seriously!!

Alright, I’m a little bit uneducated when it comes to sex because I’ve been sheltered forever but I had sex with a guy unprotected today he didn’t cum inside of me and it’s the day before my fertility window closes. I was thinking of going to the ER tonight and getting a birth control prescription? But I need answers and advice? I can’t afford a plan b it’s $65 and I know I shouldn’t have had sex unprotected idk what came over me🤦🏽‍♀️