I got the same symptoms with you 10 years ago. But now I never missed a day of sleep and many times could fall asleep under 1 min.
Here are the steps you could try:
1- Go to Youtube and look for some videos about animals abuse such as live chicken are ground/crushed under grinding machine in some food factories so that we could feel not very depressed about our lives since we know that there are some living things still more misery than us a billion times. ( I am not kidding, since brain/emotions are too complex to be controlled, so we should do some kinds of training by real experiencing to put them in check).
2- try some breathing meditations to slow your brain waves to alpha state. I followed the breathing exercises according to Dr.Weil cassette. (I bought it for $5 or sth , but it 's greatly help). I used to do this exer around 6pm, but it helps with my sleep at late night. (for summary, for those exercises you just slow your breaths, hold your breaths, or tongue touch upper teeth with fast breathing; if do correctly you will yawn continuously i.e a good sign of sleepy)
3- Read books or Internet until you feel very tired. That 's the key . I found out that if I tried to sleep to early, I hardly fell asleep. If you try to sleep early , that means you get anxiety and that 's not good. I used to sleep at 2am.
4- When I went to bed, instead of thinking about girls and stuff like before, I just tried to recite what I had learned (school stuff) during the day or previous days (recite in head , imagine the locations and contents of what I read but not have the kind of inner voice reciting). This may be similar to the one-point object mediation in Yoga but I think it 's better because focusing on one obj in meditation is so boring and did no help to society.
This helps me to sleep easily since I just try to recite and not worry about whether I could sleep tonight or not, so I wouldn't feel frustration if I couldn't sleep. That's the key since last time I got insomnia coz I worry too much about the outcome.
5- In short, the key factors are: love, calm, positive, work hard, try to stay up late instead of trying to sleep, breathing focus.
PS: When you want something so much you could never get it (because of anxiety), but if you just trying to do your routine with a beautiful mind then you might obtain it on the way.
If we recover from our miseries, we know that there are still many miseries out there in the world, so from then on we could try to behave well (such as work hard towards helping animals...)
Please write your result here if you ever try my ways. Thanks and best wishes.