How long do most people bleed during the first trimester?

I have been bleeding for a week now. I had an ultrasound 5 days ago and the dr. told me everything was OK and not to worry. The heartbeat was at 128. Then the next day the bleeding got heavier (although it was still lighter than a period) and there was some clotting. They are currently testing my hormone levels and I am waiting to go back in a few days to have them retested. Meanwhile the bleeding is back to spotting however there is still some clotting every once and a while. Has anyone ever had this happen to them with positive results? I am very worried while waiting for my hormone levels to be retested