Late period - could I be pregnant?

I had unprotected sex in the heat of the moment about 2 1/2 weeks ago, we did use the pull out method. My period is now 6 days late with extremely light spotting. I have recently come off the pill a few months ago as I wasn't sexually active and my periods have been a bit irregular. Could there be a possibility that I may be pregnant and should I take a test or just wait it out? :( help!