Whew! That was scary!
Honestly, it was like someone poured blood all over my carpet, and then it just wouldn't stop. We went through 8 or 10 paper towels soaked with blood.
Okay, I called my vet's office and left a message on the answering machine, even though there is no one there on Sunday. And my vet (bless his heart) called me back and asked some questions and then said:
If it is coagulating blood, it is some kind of tear up inside her.
If it isn't coagulating it is like all of you said, and is just blood from her heat cycle, and as bjh said we just "unstuck" her.
Put some counter pressure on it, sit with her for awhile and see if she continues to act normal. Check her gums to see if still pink. It is probably okay and will stop on its own.
OKAY -- so I feel so much better. AND I really really want to thank all of you. You were my first line of information -- and you were right. You can't beat that. Thanks again.