When my friend got pregnant, she said she kept feeling like she was going to have her period but didn't. It is possible that you are pregnant since you had unprotected sex. Is your period due in a week or is it past due? If you're late on you're period, I would definately take a pregnancy test. Then you will know either way. Also, make sure that you don't do anything that wouldn't be healthy for pregnancy until you know either way. Good luck and let us know.

Planned parenthood tests are cheap and reliable.