Terrified of a miscarriage... Please ...?

I am in the very early stages of pregnancy but i'm absolutely petrified of a miscarriage. I have a very demanding job and i'm up on my feet all day caring for adults with a wide range of special needs, so i'm really scared I could have a miscarriage. Is there any help to avoid one? Or can this not cause a miscarrige?? Please help me and answer my worries... I would greatly appreciate it :)