Shift work affects normal sleep cycle.
As it’s part of your job you need to make some life style changes which might help along with medication.
Cut down on caffeine intake, avoid any caffeine drinks and smoking at least 4 hours, before your sleep time .use ear plugs and eye covers if you are usually disturbed by slightest of noise or light.
Optimisation of melatonin dose and time you take it , try to take at least an hour before your sleep time would help as well.
Some medications taken for physical health issues can keep you awake.
Next Steps
If still having problems with sleep consult a psychiatrist online book a appointment through Practo to consult with me