Yukio, just look after yourself as well as you can, and follow what they have told you to do now that you are pregnant.
You're still young, and once this is over and done you can get back to being as healthy as you want to be with your two little babies.
It's not a bad thing that you did this and followed the plan so far, because you know have knowledge that I sure didn't at your age, and you know what to do to keep on top of your diet and weight if you ever want to. What I wouldn't have given to know all that 20 or 30 years ago! I have tried lots of other things with little avail, but finding this has been an incredibly powerful tool for me.
I hope all your plans work out for you. You've obviously had to go through a lot following hubby around with his career. For some it's a lot harder because of issues like that, but you will have lots of experiences together and enjoyment to look back on over the years.