Oh lisedea, I'm sorry you are bleeding and cramping. Can you call your doc/midwife? How far along are you? About 5-6 weeks?
I'm not sure if this helps at all, but the day after our first ultrasound (when we saw the babies' heartbeats and learned we were having twins) at 6 weeks I started bleeding (huge clots like I've never seen. I described it as hemmoraging) and cramping. I was, needless to say, hysterical. We rushed to our midwife's office and it turns out I had a whopper of a subchorionic hematoma (uterine bruise). The bleeding stopped the next day and I haven't had a problem since.
I'm really hoping this is what is happening for you. But if not and it is a miscarriage, know that you are among friends who have been through it. I had an early one, my partner had an early one (and she got pregnant w/our DS two cycles after hers).
Take care of yourself and know that we are all thinking of you.