I had unprotected sex 5 days before my period, but missed my period.I took a test(clear blue) 3 days after missed period, it was negative.started my period after a week, and had unprotected sex on the 2 day of period. Is it possible I could be pregnant?

Any time you have unprotected sex there is a possibility of pregnancy. ANYTIME. But in this case, I'd say the chances are lower. While you can become pregnant during your period, it is not as easy as when you are ovulating. Unfortunately, there will be no way to know until your missed period, or at least a few weeks out with a pregnancy test. Just to confirm, are you trying to become pregnant? If you aren't then maybe you should consider one of the many forms of birth control available. If you are, timing intercourse around ovulation is best. Good luck!