DSPS- sleeping 3.5 hours on Melatonin.

Hi, I've got DSPS since I was 17. I'm 25 now. Nothing helped so far. I've tried Melatonin several times and had nightmares. This time they are gone. I take a slow-release version of 2 mg, and I sleep at a reasonable hour, but only for 3.5 hours.

What can I do to sleep at least 6 hours at night? Should I try to combine the Melatonin with a benzodiazepine?

Any help will be great. Thanks in advance.

sometimes buspirone helps me sleep by cancelling out the biochemical state of things preventing me sleeping. dont have any atm though. Research has suggested most dsps is psychological. In my case i think the dsps is caused by biochemical changes which are caused by psychological elements, e.g. levels of adrenaline vs cortisol etc.