They probably were talking about her - Vietnamese love to gossip and commenting on all sorts of 'personal' things to your face is perfectly OK.
It takes a while to get used to people saying things like "you're looking fat today" as a greeting :)
Sounds like you've got the right attitude to enjoy yourself here. Give me a yell if you want to chat over a beer when you get to Hanoi.
(I'm geezus from before btw, not sure how that happened)