scared!! :(

This is my first pregnancy so of course I'm learning things as they come. I'm about 6 weeks pregnant ( I thought I was 9 1/2 weeks) and last week I started spotting. It started off as a brown discharge. I didn't worry about it too much since it wasn't red and I wasn't in pain. This week I have had more discharge than last week and pink in color as well. I decided to go to the ER to get looked at. I did a urine test and noticed that I passed a blood clot. I freaked out because I didn't know what was going on. The doctor did an ultrasound and he found a sac but said it was too early to see a baby. They decided to do some blood work and when those results came back they told me that my HCG levels were low. Of course getting all this negative feed back makes me think I am losing the baby. I have to do more tests in a few days and they will then determine what is going on. i passed another clot this morning. any advice? anyone out there with the same situation?