Delayed Sleep Phase Syndrome

I do realise this topic is almost a year old, but I thought I’d just go ahead and revive it rather than starting a new one on exactly the same subject.

Anyway, I really think I might have this - or at least something with similar effect on me. It first started back in September - the time at night when I would be able to sleep kept getting later and later - there was a time it was about one in the morning, but by the very start of October it was after five thirty, and occasionally not until after six. I needed to be up at nine every morning to get to my university lectures, and within a week that just became completely impossible as nothing I did could get me enough sleep to feel able to do things, unless, of course, I slept until the time when I would naturally awaken - or at least close to then (which was around three thirty in the afternoon).
Then, a few weeks ago, after two nights without sleep, I somehow managed to partially fix my problem - I managed to get to sleep at ten and waken up at around five. However, for the first few days of it, it started to become very difficult to stay awake after around three in the afternoon, and if I hadn’t had a cup of coffee I probably wouldn’t have stayed awake until dinner - then, of course, I was exhausted all evening and when I went to bed at ten, I fell straight asleep. As the days went on, the period of exhaustion took longer to begin - it wasn’t starting until around nine, then ten, and by end of the week before last, it wasn’t starting until after midnight. And by the start of this week I was completely unable to sleep until after five…

I’ve been to see two different doctors and haven’t had anything done about it - they all seem convinced that it’s just insomnia caused by my depression and stress (which do exist), and haven’t quite understood me when I say it doesn’t feel that way at all as I have no problems falling asleep after a certain time, and I don’t feel at all tired before then. My mother’s also of the same opinion as they are - and no-one seems able to comprehend what I mean when I say that my sleep patterns feel completely natural…

Edit: 2:52 am.
As I’m still up - I’ve been lying in bed for over an hour now, which is the second time I’ve done that tonight - I thought I’d update. I’m actually sort of tired, which is unusal, but I can’t for the life of me get to sleep: lying in bed seems only to serve to make me feel more awake with each passing minute…
I need to be up at eight tomorrow, and if things keep going the way they are, then I’m either going to have to spend tomorrow feeling thoroughly groggy (for two hours sleep will never suffice), or just forego sleep entirely. Either way, tomorrow shall not be pleasant.