Hydration!

Day 3:
It is the beginning of day 3 and I'm already losing motivation. I put on some old pants today and they felt tight. I'm a stress eater, and I got my first teaching job in December, so I am stress eating up the wall, and I am using this new job as an excuse not to exercise. I go through phases of motivation, but then when those phases are over, I am twice as bad at eating and exercise, and so I've gained a ton of weight. I am officially at the heaviest I've ever been, and I hate myself. It is really hard to stay motivated because both my boyfriend and I are emotional eaters, and its easy to just give up together. I know that he loves me no matter what, and so part of me doesn't care what I look like, but then part of me has a hard time when I can't fit into pants!
One thing that I am having a lot of trouble with is staying hydrated. Being a teacher makes it really hard to drink water since I can't visit the bathroom whenever I want to. It's a curse really. I want to drink a lot of water everyday, yet I am being held back by the fact that I can't make it to the bathroom unless it's lunchtime of my prep period, which is first thing in the morning. So how do I stay hydrated, but still teach all my classes? This is the question.
Another problem: happy hour. Unfortunately, I'm at that age where happy hour and alcohol and bad for me food is a weekly occurance, and it is awfully hard to say no to all of those things. Who doesn't want a drink after a long day at work? I've started looking at the menu and calories before I go so I am aware of what I'm getting myself into.

Sometimes I wonder if I could do it. Can I lose half of my body weight? Can I lose 20 pounds? Can I train myself to be a good eater and not eat bad food when I'm stressed or sad?

Can I do this??????