I have been bleeding after a few of my runs as well.
I have had bleeding nipples, thighs so heavily chafed that they were bleeding, a few black toenails and last week, when I was running in the dark and did not see a low-hanging branch, a bleeding head!
If it is vaginal bleeding you are talking about, there may be different reasons for it, some quite innocent. In that case, and any bleeding that you cannot explain, it is best to just visit your physician. That's really the best person to find out what is going on and to put your worries to rest.
Do you want to run your first or fastest marathon? Find out how to train for a marathon the right way with the 100 Day Marathon Plan. Of all the marathon plans I have seen this is the best.
When you are a runner, you are doing intervals. The Gymboss is a really clever and cheap piece of running gear that makes interval running a lot more comfortable. Check out the Gymboss review to find out why.