12 weeks pregnant, very nervous with questions?

I'm just about 12 weeks pregnant, and I've had 2 previous miscarriages, both happening around 5-7 weeks. I know a miscarriage can happen any time.. But as you get further along, do you still run the risk of your baby just stopping to develop? I guess I'm really nervous because there isn't anything wrong, besides my nerves, i don't feel symptoms that often right now, and I don't feel my stomach is grown at all in a few weeks. But I've had no severe cramping, or spotting/bleeding. At this stage in pregnancy would you still miscarry without symptoms? I know I'm just setting myself up to be freaked out, I'm just curious..

Please give your advice...