There is an article on bleeding in pregnancy on the main page, its not uncommon, I think 1 in 5.

If you are worried, call your doctor or midwife (sorry, not sure how far along you were)

I had pink discharge at 6 weeks, but it was all day, every time I went to the loo.
Then at 8 weeks, I had dark red/brown mucous too.
And now I have a healthy almost-10 month old!

I was really worried though, boht times, as both were after exercise, and both were accompanied by stabbing lower abdominal pains, so I had an ultrasound which showed that everything was fine.