Big Scare!!!!!

Yesterday I woke up to find a moderate amount of brown spotting when I went to the bathroom. I was not cramping or having any other complications just the spotting. I decided to go to the MD to see what they thought it could be. After having a transvaginal ultrasound the MD said that the baby is smaller than what they thought it should be so we may have the estimated age wrong, I was thinking that I was 7 weeks pregnant. He also said that I could be having a miscarriage or that it could be where we had intercourse recently. He was not very positive to me at all, kept saying miscarriage, and said that he wants to repeat the ultrasound in one week to see if the baby is growing or not. He didn't even do an HCG level because "there is no use in it if you are going to loose it". Now I am really scared and trying hard not to panic. I am still having light brown spotting and it is getting lighter and lighter each time I go to the bathroom. I still have all my pregnancy symptoms too. HELP!!! I am soooo scared!