Hi Jamie.
Your health is more important than a job. I don't know the details of your situation, but it doesn't sound good.
Just some things to consider, don't be alarmed;
1) Levels that high, you will do you more harm than good long term.
2) You need to have regular drink/food break intervals to control spikes in blood sugar levels.
3) Sounds like your boss is breaking a lot of employment rights. Go seek advice.
The main issue is that you must do what is best for your body and your health.
It doesn't sound like your happy in your work, this seems to be the main issue here. Stress, working conditions and a pushy boss.
Try to make small positive changes in your lifestyle every day, then that way your health will follow.
Find a way to destress and uncomplicate your lifestyle, you take control of the challenges ahead of you.
I hope you get your levels undercontrol and feel better.