I don't know if I was bit or not... Help?

I was in my kitchen and felt a bit of a sharp sting, like a pin prick, on the back of my left leg. I swatted at it, thinking it was my shorts snagging some leg hair. Couple seconds later, I felt it again and swatted again, then I looked to my right and saw a black shape, maybe a quarter in size, less than two feet away from me, and it was scurrying away FAST. I couldn't tell if it was a cricket or a mongo spider, or if it had even been on my leg in the first place, but brown recluse spiders live in my area BIG TIME, and I'm freaking out about this. The "thing" was about the same size as an adult recluse, so I'm worried I might have just received a spider bite for the first time in my life. What should I do? Brown recluses are venomous, and are rarely fatal, I know that, but I don't want to lose my leg! What should I do?