Paranoid..

So I've been really paranoid for the past couple of days because I am having lower back pains (my doc says it's my uterus stretching) but I'm still nervous and I haven't had any vomitting from morning sickness in the past 2-3 days. I still have been nauseous and moody and my boobs are sore still. But I read about a "missed miscarriage" and now I'm freaking out that I had one. Are there any symptoms? Is it common? I had a MC back in the beginning of June so I'm a little paranoid this time around my doctor is very understanding and she gives me ultra sounds weekly but my next one isn't until Tuesday :(