I also have sleep problems: though not so extreme (I sleep fitfully and often cannot sleep for a whole night - maybe once or twice a fortnight).
The advice from swombat is the BEST you will ever get.
DSPS is, as noted, incurable. However you can train your body to ignore it with serious discipline (or rather train your body to a decent sleep pattern). I'd hazard that your age (24 right?) is amplifying your symptoms/problems.
You only need 7hrs of sleep a night (some people can manage 6) to be rested: the key is getting some REM sleep in there (my main problem is that I sleep in 60-80 minute cycles and deep sleep usually doesnt start until 90mins into a cycle). If you sleep deeply when you DO sleep then you will probably be ok.
Have an extremely strict bed time schedule. So at 10 (perhaps) begin to wind down. Have a bath (I find this to be the best thing) for 20 mins. The sit and read a book (not in your bed) prefferably a boring one - I am hugely well read for my generation because of this :D. At 11 (dead on) lie down and dotn TRY to sleep. Relax and clear your mind - think of what your plan for the next day is. Build an itenary and imagine how the day will go. Whilst you do this breath very deeply. You should relax and fall asleep.
If you find that your still awake after 45mins (30mins is not unusual for the amount of time needed to fall asleep!) then get up, walk around gently for 10 mins (or read).Then try again.
In the morning have the alarm set for, say, 7am. When it goes up get up - no snuggling or whatever force yourself out of bed w/e. Then have a really good energy breakfast and do some exercise. This will clear the "sleepiness" out of you (which will make you feel sleep deprived when your not).
Other tips. Make sure you snack (healthily :D) through the day to keep energy levels up and your metabolism going. DO NOT eat a big meal any closer than 3hrs to your bed time (so if it is 11 then make sure dinner is well done by 8pm). Drink plenty (of water) through the day but avoid drinking it before bed time. Also avoid cafeine like the plague (this will keep you awake fort hours if you have even a slight sleep problem). You could try herbal remdies to help sleep in the evenings (I take some now and again when I cant relax) or eat foods like cheese etc. in small quantaties about an hr before bed.
It will take work and you might feel rotten for a week or so. But eventually your body will adapt to the correct sleep pattern.
Also get a second opinion: DSPS is often a "get out" clause for sleep conditions :) I was diagnosed with DSPS a couple of times before they got ot the bottom of it. My specific case is that I have sudden releases of seratonin in the brain (the stuff that chocolate and sex generates :)) so I go hyper for short spells - which wakes me up or keeps me awake. It does wonders for my creativity but can destroy sleep patterns :)
A lot of your issues are probably also down to being young (I am around the same age and a lot of my problems are gone now simply through discipline). Get rid of those and you will then have the core of your sleep problem laid out reayd to address :)
It will be tough - so good luck. But with a LOT of discipline you'll make it!