Like others have stated, sleep disorders are sometimes symptoms of underlining health-related concerns, especially mental health issues.
I have suffered from clinical depression my whole life, and like I mentioned in a previous topic on depression, my major symptom is sleeping all of the time. If I experience a traumatic experience - stress at work, relationship crisis, death of a loved one, etc.- I will automatically get so tired that I'll fall asleep where ever I'm at. I could literally sleep all day and all night if I could get away with it.
Again, as I mentioned in the earlier discussion, I got addicted to caffeine, sports drinks and weight-loss supplements because I relied on them just to make it through the day, which was counterproductive because they created a vicious cycle. After they wear off, you become even more lethargic and sleepy, thus worsening your sleep problems.
I don't know you personally, but I am interested in knowing if you have ever been to a counselor, therapist or psychiatrist. I'm not trying to say that you do indeed have a problem, but 50% - 80% of people suffering from depression, anxiety, BPD, ADHD or other mental health disorders are affected with sleep disorders compared to only 10% - 18% of the general population.*
There are many ways you can help resetting your internal clock - The Circadian Cycle - with or without drugs. I said this many times before, and it's worth repeating here again. Exercise, exercise and more exercise! A healthy body is a healthy mind. Proper nutrition and exercise are crucial for mental well-being. Certain foods can have toxic effects on brain chemistry, like too much sugar in ones diets and many chemicals that are found in processed foods. Try to eat plenty of nutritious foods that feed the body and the mind, and then engage in vigorous exercise to help stimulate the circulation and gets the blood pumping, which increases blood circulation to the brain, not to mention releasing a lot of "feel good" hormones and endorphins. Plus, if you workout hard enough, your body will be exhausted and you'll be forced to fall asleep.
Another helpful tip, and something so simple, is not to eat, watch television or do anything in your bed other than sleep! I know many people are going to be like WTF! But for those of us suffering from sleep disorders, it's a must. If you only sleep in your bed, and nothing else (well, except for sex, of course) you train your body/mind to only view bedtime as something for sleep. If you are reading, watching television or eating in your bed, then your body/mind views the process of lying down as an activity which requires mental alertness, not something that requires relaxation and rest.
You can also train your body/mind by wearing the same bed clothes each night that you go to sleep, thus programing the mind to anticipate sleep. Don't wear your sleeping clothes for anything else but sleep. When you put them on, you psychologically signal your body that it's time to go asleep.
You could also try melatonin to help reset your Circadian Rhythm. It's natural, non-habit forming and inexpensive. Take it an hour or two before you sleep, and it should help calm the mind and make you stay asleep throughout the night.
Meditation is another alternative you can try, and believe me, I always fall asleep whenever I try to meditate. Whenever you meditate, you try to clear your mind of all thoughts, and if one happens to come by, then you release it and try to focus on emptying your mind again. It's just an act of mental house cleaning, which helps clean out all of the clutter and chatter in the mind. Every time you have a thought, you let it pass and re-focus on the inner peace and stillness of the mind. Don't force it, tho, or it won't be meditation and will likely drive you mad. Just go with the flow until you fall asleep naturally.
If all else fails, then you could always work nights and have an opposite sleep schedule as everyone else and just get a night time job. I actually did that a couple of years ago. I worked at a hotel as a night manager, so I went into work at 11:00pm and got home about 8:00am. If you can't make your body do what you want, then create your life around it.