Sex pregnancy scare

I had sex with my boyfriend a couple months ago. We did use a condom but I got so scared of being pregnant after I had to rush around to come up with 50 dollars so I could buy plan b just to ease my nerves and I took plan b 2 days after. I then got my period about a week after that so I knew I was not pregnant. But until I got my period I was so nervous and miserable I just want to be able to have sex with my boyfriend and not have to worry about the constant pregnancy scare. Advice?