brown spotting after internal ultrasound

I had my ultrasound (internal) yesterday. I'm 7 weeks and today when I got home from work I noticed I had some brown spotting. 
I know, I know, brown can be old blood left over. 
I would just like to hear from anyone that has had something similar happen.  
My doc had me run in and have a quick blood test, which of course I won't hear back from until tomorrow morning. 
Did anyone go through this?