Could I Possibly Be Pregnant?!

Soooo I made this huge mistake and had unprotected sex with a guy that I ended up having a one night stand with. He did not cum inside me he "pulled out" however, im still scared. I woke up the next morning freaking out and I called my best friend asking to help me buy a plan b because I didn't have the money together to buy one myself. I know what I did was irresponsible and I am not old enough to even be having a child right now. I've been freaking out about it but it's been 5 days since we had sex and I have no idea when to take a pregnancy test or what to do. Help!!!!