Wow, it sounds like you were really between a rock and a hard place today and came through it all with flying colors! I know what you mean about the perfectly good veggies, covered in cheese, and the guilt from mom. Every once in awhile, I have to be really mean to my mom to get her to back off about the unhealthy foods. She brings freaking CANDY over to my house, sometimes! She has gotten a lot better about it in the past several months, but it still gets extremely frustrating, from time to time.
Just continue doing what you are doing, and don't let other people mess you up. Perhaps if you are going to get stuck at a meal you don't want to eat, you could find a way to grab a healthy snack on your way over, or even eat a good-for-you meal before you get to the bad-for-you meal, and then you can just have a little bit of this and that.
It feels wasteful when I do it, but it's better than NOT doing it.
Edit: a tasty drink that is not water? I like Peppermint, Lemon Blossom, Chai, or Licorice spice teas. I'm trying out some apple spice tea, as well. They are cheap, especially compared to soda, have no calories, taste very sweet, and are good iced or hot. The expensive ones are about $3.50 for a box of 20 teabags or 17.5 cents a serving. You can't beat that deal, and most of them are a LOT less.