Heavy Bleeding Baby Ok Heavy Bleeding?

Heavy Bleeding? - heavy bleeding baby ok

OK, 18wks preg. was rushed to the emergency room last night because my bleeding, I had decided that since I 12wks flow of non-stop (enough to fill a beer), a blood clot the size of a tennis ball. Finally it subsided within about 2 hours and let me go home after he checked the cervix and the baby's heartbeat. Cervix is closed.
I went to the gynecological evaluation, in which we now turn to examine the cervix and the heartbeat and told me to wait until my 20 weeks scan. Why do I now personalized analysis of what's new? She said if the baby's heart rate was not heard or irregular then I will scan, but if Babs gallop. They told me since I started with all the problems.
My blood is like a period now and I'm not so worried about the child, butAcross the placenta, blood clots, anemia, etc.
What is possible?
And another thing, if the formation of blood clots / os, how about getting to the mucus plug that seals? Or is it someone there?