I'm sorry they can't get you in sooner. This just sucks! At least you are only having brown spotting....that usually means nothing serious. I agree with the ladies, as long as bleeding is minimal (not bright red, not tons) then I would try to wait it out until the appt on Monday. If it does start back, I would prob. head to the ER just to be safe.
I'm sorry you are having to worry about this. I really hope it is nothing and everything is OK. I do also remember with DS1 that I had an u/s at 12 weeks b/c they couldn't find the h/b. My fingers are so tightly crossed for you. Big hugs!