I never got used to switching from day to night and days off were spent mostly sleeping.
Eventually it came to an end, after about 8 years, and I returned to the land of the living, working 9-5. The adjustment was difficult and the drop in income wasn't much fun either.
I ended up changing jobs every few weeks because there was always some reason to leave and eventually I just stopped working altogether. I didn't know it the time but I was drifting into a severe depression that lasted several years and ended with me living on the street.
I can't say for sure that working nights for so long set me on that road but I have a strong suspicion that it was a major factor.
I got lucky after a short while, got back into work and it's all just a bad memory now. I do wonder where I'd be now though if I'd just stuck to working days, like most people do?
One of the best business models is, selling something that is mandated. Like cleaning restaurant floors (health and safety rules).