Stopped taking pill, had sex unprotected, chances of being pregnant?

Okay, so that title is a little bit callous, it's just a quick question about the chances of my being pregnant.. Basically I'm used to using the pill, but I decided to come off it recently and go back to using condoms purely because of other side effects it was giving me. My last day of taking it landed on a Tuesday, however on that Friday I had sex unprotected- stupid I know but I was still in the mindset of being on the pill, a mistake I won't be making again; the thought didn't even occur to me until the day after when my period came. In my head I freaked out a little because I thought that the pill only worked for each day you took it, but by having my period I figured that it meant I wasn't pregnant. But as you can see- I'm not an expert on the subject. I planned to go to my clinic to get checked but it's far out of town for me and usually a long wait while I'm there. I feel like I should go to be on the safe side however I wanted to check on here first to make sure I'm not being ridiculously paranoid. I've had no symptoms or anything to give me concern and I don't fancy taking a day trip out to the clinic only to be told that the chances of my being pregnant in that situation are more than unlikely. Is this all in my head, or should I actually go get a test?