Re: Help on losing weight.
I think you should consider if you are eating enough calories in order to widthstand the physical strain for your job.
Some alternatives to caffeine for energy are nuts and fruits. The days my husband works long hours, I pack his lunch with fruits and almonds. He says that the almonds help him stay awake on the drive back home. They are easy to pack and munch on.
You just have to be careful not to overdo it in terms of overall daily calories.
As for your ankles... there is no muscle there, mostly ligaments. So, it will be difficult for you to strengths your ankle as there is nothing, in theory, you can do about it.. except to take your breaks and basically, have management respect your schedule.
In my opinion, there is no job too good to sacrifice your health. I worked in a popular fast food chain in my youth and when I had enough, I had enough and left to find myself a better and more relax job.
I know this has nothing to do with fitness but I find it odd that people accept abuse from a boss and do nothing about it. It's part of your life and your lifestyle.
If you don't like it there, I say leave.
Meanwhile, you can try nuts and fruits for energy and taking proper breaks.