I'm so sorry! Bleeding is very scary during pregnancy! There's no way your doctor could get you in for an earlier appointment?
Bleeding with clots is not a good sign, imo. It doesn't absolutely mean miscarriage, but I would be concerned. Were you able to leave a voice message for your doctor? If it is a miscarriage, there isn't anything anyone can do, unfortunately. I'd suggest that if the bleeding becomes really heavy, like you are filling a pad in an hour, then you need to go back to the er. I'm sorry you're going thru this and just wish you could speak with your doctor. Thinking of you and hoping all this turns out fine and you still have that liitle bean safe and healthy inside.