How far along are you also is a factor?
I have had 2 miscarriages myself, and was told I had a threatened miscarriage with this pregnancy (was 14w at the time, now 34). Working generally isnt going to make your chances of miscarrying go up, and if you feel like you need the day off to help cope with being told you have a 50% chance then do it.
There is nothing wrong with taking a day off to step back and gather your thoughts.
And talk to your doctor about restrictions in case they want you to rest.
Wishing you the best of luck