Some spotting can be normal but definitely let your doc know in the am.
Yes, definately see a doctor and get a an ultrasound, I had a miscarriage that started off with brown discharge, and with my last pregnancy I had the same bleeding at 7 weeks, but he was fine, it was a hematoma. The only way to know for sure is to get checked out. Oh, and I had no cramps either, with the miscarriage and the hematoma.