Is it safe to take extra vitamin b12

So I am 5 wks as of tommorrow and was reading that b12 deficiency can leave to preterm labor and other complications and I found out the beginning of this year I had a pretty bad case of b12 deficiency (( my levels were 400 and the lowest you should be is 900 and highest is I believe 1900 or so) but anywho they prescribed me a high dose of vitamin b12 to take daily till my levels got to normal and they did but that was months ago and they haven’t tested me again and my first ultrasound isn’t even until November 19th 😩 when i will be 10 wks and I am curious if I should keep taking an extra dose of b12 although my prenatal has a little bit or wait and see what my doctor says also does anyone know if charcoal detox is okay to take ?