Hair lost during pregnancy

Nancy
I am 13 weeks pregnant. I am reading that you are suppose to get better, stronger, longer hsir due to the progesterone and the pre natal vitamins, and that the hair falls AFTER birth. But for me, it has been falling since month 1. I take my vitamins and try to eat healthy but I am worry because a lot is falling and I don't have a mane if hair :( I don't want to imagine how will it be after birth!