I was the same with my 2nd pregnancy, and a LOT of women told me they were with their 2nd. I for some reason had a looming fear of miscarriage. I'm 30 weeks 3 days and still worry I won't have a baby at the end, it's a normal worry to have, just try not to let it consume you. After 12 weeks you have a very good chance of a healthy pregnancy!
I've been doing that my whole pregnancy too. I've been so paranoid and anxious. I'm 34 weeks today and even though it is still far too soon I felt a huge sense of relief knowing that even if I has my baby now she would be ok.