How To Confirm Pregnancy?

I was forced to have sex about 7-9 days ago. Before then, I was a virgin. So it was my first time. I'm afraid that I may be pregnant. I was wanting to pee on a pregnancy test stick tonight, to find out. Do they have a chance that if I'm pregnant, can I find out tonight? Or do I need to wait? The last I was on my period was over 3- 4 weeks ago.