When is the appropriate time to take melatonin?

ive heard to take it like an hour before your natural sleep pattern. what if my natural sleep pattern is 4-5AM? ive been on that streak for a year now even with college i just drag myself through the day on 3 hours of sleep or whatever then stay up till about 4-5 then get up around 1-2PM. so im looking for a good time to take melatonin since a sleeping pill wont do sh!t considering how ive tried to break this with lots of excessive and all these methods, didnt help.