Chacha sweetheart you have got to chill out or you are going to make yourself ill. Pregnancy especailly your first is supposed to be exciting and full of anticipation, not full of dread.
I can't answe your questions re m/c as I have no experience of it and please don't think I'm laying into you here, I'm just worried that you are stressing yourself out which is not good for you or the baby.
At the moment you have a perfectly healthy baby, you've seen it on the screen and you've heard it's heartbeat, there is nothing more you can do other than to take care of yourself, eat properly and take your vitamins. It is scary seeing all the others going through there miscarriages but if you weren't on this site you wouldn't be aware of how often it happens. To be honest I certainly wasn't and it has freaked me out a bit too.
You could by yourself a doppler which would enable you to listen to the baby's heartbeat at home but to be honest you just need to relax, the more stressed you get the more likely something bad will happen. Just enjoy feeling crap, as this is a good sign and then enjoy getting fat you'll feel a lot better after the 12 week period and when you can see a bump develop.
Now if the sun is shining where you are get yourself away from this computer and enjoy it. Hope you're not offended by the straight talking