Traveling Wk8-12 to Tokyo/Vietnam - tips?

Kathy
Hi,
We booked our travel to Japan and Vietnam already before knowing I was pregnant. I am 5w4d and will be in Japan during my 8th week and in Vietnam week 9-12.
Any tips, advice on what I should prepare before my trip, bring with me to help make things easier, airport security (can I go through security x-Rays?), street food precautions, fresh sushi in Japan (can I eat? Japanese pregnant women eat sushi all the time?), things to ask my dr during my 1sr prenatal visit right before i travel... Thanks in advance! :)