T.W.
I traveled for my job up until 7 1/2 months pregnant with my first one and like you, I tried to eat perfect and all that. I just carried a huge purse and made sure it had every snack I loved in it, including water. It was a huge pain but it worked. Now that I have had 4, I came to realize that once and a while, eating a bit of junk only hurts you, your body typically filters the bad stuff and the good stuff goes straight to the baby. So try not to worry too much.
Good luck.