Unfortunately, most people really are clueless about weight loss and maintenance. It really does entail a lot of effort and dedication, as it won't happen on it's own. I think the girls at work don't realize how hard you've worked to get off those 40 lbs. 40
lbs!!! A week in Vegas, eating "what you want", could very well wipe out a nice sized chunk of that nice sized loss.
I know if I eat and gain I will be super depressed. I know I need to just eat right like I have been but I guess I just need to hear it from others telling me to stick with it
Stick with it. Eat right.
Don't let a little vacation stand in the way of your hopes and dreams. Giving yourself permission to "eat what you want", could really be a disaster in the making. You're eating will most likely be "off" regardless, since you are not at home. Do your best. Have a plan in place for how you will deal with the meals and you are sure to be fine. I find that no matter what the situation, I am much more confident and do much better having a plan in place, even if it's not my usual plan.
Enjoy your vacation. There's lots of fun to be had and it doesn't necessarily have to revolve around food.