Sigh, I am also starting to feel the same way with my current contract job, it's getting more and more dreadful working here, staring at the computer screen for 12 hours monitoring without much rest time since the job is related to cyber network security and we are required to be on heightened alert at all times.
Although its a 4 days shift work, the job requires me to make & handle phone calls which I feared a lot and barely got a hang of it.. the workload, the workplace restrictions also leaves a lot of space for me to wander and dwell on negative thoughts as well.
This 40 over hours workweek is really taking a mental toll on me. I'm starting to feel like throwing the resignation letter and live on my own terms.