Low b12 levels 33 weeks

Hey, I had a call from my midwife earlier to let me know that my iron has dropped lower, despite starting iron tablets and also my b12 is very low. She said the recommended level was around 196 and mine was 101 ng/l. I have been feeling extremely tired and been having frequent headaches but I’d put this down to normal pregnancy symptoms. Has anyone else experienced this and was your baby okay? I can’t stop worrying that the baby has been harmed in some way. I’m waiting for a call from the hospital to arrange injections but I’m just overthinking everything. I don’t know what could have caused the deficiency as I eat a regular diet.