I've an irregular sleep cycle due to my night shift work. how can i take care of my health?

The real answer?: Do you want to take care of your sleep issues due to night shift work in the most MEDICALLY SOUND & optimal way possible? If you're answer is YES then, the solution is simple. Get a job that has hours or shifts designed so that you can get proper sleep and restorative time for yourself. If that's not possible then, unfortunately, in my opinion, other solutions are always going to be suboptimal.

If you can't: change your irregular work schedule, make sure you exercise, avoid stimulants about 6 hours prior to sleep time and consider taking some sustained release melatonin 1 hour prior to sleep time. A massage now and then would be a relaxing treat if you can manage that also. Peace and good health.