Birth control help?

I'm in college and have no desire to get pregnant right now. My boyfriend and I always use a condom during sex, but I'm always so scared that I'm pregnant afterwards. I know condoms are pretty effective, but I still freak out until I get my period again. What are some ways I can limit the stress and just enjoy the sex more? Should I also ask him to pull out? Or is there another form of birth control I could use in addition to the condom?