I'm no expert, but I did have some rectal bleeding this summer and there are many causes. Cancer, polyps, hemmorhoids, an anal fissure, Crohn's, ulcerative colitis, certain infections... It's quite possible, even likely, it's something minor. You're bound to worry about the more serious possibilities though, but...they aren't the most likely ones.

And the good thing is it sounds like you'll know more soon enough. I was waiting about 3-4 months from the time I started getting rectal bleeding to the colonoscopy.