It sounds like you have a lot of stress in your life which, along with your fear of miscarriage, can actually increase your chances of having more miscarriages. The world works on the Law of Attraction...whatever we wish for, we get.
If you are concentrating on NOT having a miscarriage, you are still focused on the miscarriage. See yourself as having perfectly fine pregnancies with no thoughts towards trouble or illness. Don't feed those negative thoughts anymore.
Also, two full-time jobs, full-time school, AND a home business? Sounds like your plate is really full. Is there any way you can cut down? It's clear you are pushing yourself too hard and that takes a BIG toll on the body. You can't expect your body to perform correctly if you are overworked, stressed out, and fearful.
Meditate at least 5 to 10 minutes everyday (in a quiet place with no phone or other distractions), exercise (just take a 10 minute walk), and eat right (no greasy fast food!). I know your doctor would tell you the same thing.
Don't sweat the small stuff and I wish you good luck.