I think first of all you have to stop making excuses. I don't mean to be harsh or rude or mean ... but everything you've said above is just an excuse, not a real reason you can't lose weight.
Let's look at your food first. You say you have no fridge so you have to eat junk and crap. But the truth is if you have a cooler with ice, then you can carry all kinds of things that are healthy. So instead of bags of cookies, crackers, and popcorn, you have:
baggies of chopped veggies
hummus
boxes of raisins and almonds
a dozen boiled eggs
bottles of water
canned fruit in juice (not syrup)
canned veggies (garbanzo beans, black beans, corn, etc)
a jar of salsa to mix with beans or dip veggies in
apples, oranges, peaches, pears, grapes (and you can pick up more at any grocery store at your destination)
for early on when you have lots of ice or for short trips, add in cheese, some cottage cheese, some string cheese
you still have your sandwiches - made with lean turkey or ham on whole grain bread or in pitas
throw in a couple of cans of tuna and/or chicken breast to make sandwiches on the go
pick up a salad at Wendy's or some place like that for $2, tell them to leave off the dressing and throw on a can or packet of tuna.
keep the cans of soup but make sure they're healthy ones - low sodium types
I could go on for hours with things you can travel with and still eat healthy.
Then for exercise. Is there really no way you could stand up for 10 minutes every 2 or 3 hours and do some jumping jacks, walk around the building? Even if you can't do that, after your shift is over, 20 minutes of brisk walking will not only give you some exercise, but it will help you to sleep better and be more alert the next day.
Even while you're sitting at the computer - stand up for 15 mins. Work from your computer on your feet. Knock out 20 pushups against the edge of your desk once every 2 or 3 hours (I do this at work all the time when I need a quick mental break). When you go to the bathroom, do a quick 10 squats before you return to your desk. Or do walking lunges from your desk to the bathroom and back (I do this too).
I travel a lot for work and dont' always have access to a full
gym. Take some resistance bands with you and use them while you're sitting in your hotel room at night or even at your desk at work if you're able to.
There are all kinds of ways you can get exercise into your daily routine.
Like I said, I am not trying to be harsh. I'm trying to point out that it's easy to come up with excuses why you "can't" do something .. but most of the time our "can't" is really just either resistance to change or lack of knowledge.