With DD I had some light spotting at around 6 weeks. Bleeding in early pregnancy is fairly common. A friend of mine bled all through her pregnancy and was even told at 11 weeks that she'd lost her DD who is now a happy, healthy 3 year old.

Maybe take it easy until you see the doctor tomorrow. Try not to worry until you get the HCG results. Easier said than done I know. Fingers crossed you get good news tomorrow.