can you tell me how far along i am?

haha i know that sounds like a ridiculous question. but im in germany right now. and the german doctor seem to confuse me. my german friend also told me that america and germany do due dates differently.

well my husband will be in iraq when i have the baby. his unit is trying to send him home for his R&R with my due date right in the middle in hopes he'll be home for his first childs birth. before i came back to germany i was only 5 weeks 3 days along according to the american doctor said my due date was february 24th. then a few days later i was rushed to the hosptial and they said the due date was february 27th from the ultrasound. then 2 weeks later i had to follow up with my german doctor and hes saying my due date is the 6th of march. i know its only a week difference but a week is alot if i want my husband home for the birth of his son. im either 19 weeks 6 days, 18 weeks 6 days or 19 weeks exactly. should i go with the german doctor or go with the american doctors?