Your entire life must be scrutinized. You didn't get here overnight, therefore you can not solve the problem overnight. Nutrition, habits, and social patterns are most likely your culprits.
Sugar (energy drinks) is one nitrogen and one oxygen molecule different than pure cocaine. Stay away from refined sugars ENTIRELY. It wreaks havoc on multiple systems in your body. Dr. Mercola has an excellent nutrition program that is FREE. One can easily find him on the web.
Circadian rhythms are thrown off by the light we process. You will have a hard time getting to sleep if you are on a computer, watch television, or are in a well-lit environment in the several hours before you attempt to sleep.
Social patterns such as school, family, and friends would be the most likely culprit if you have eliminated the previous two. You seem to have had a stressed-out life: missing school, work, etc.
I was in the same boat as you. I started working for myself; I do what I want when I want, but it took a couple years to get right. My stressors are now gone.
The 'way-of-the-world' is quite stressful. Leave it behind. You will find that leading your life with Truth is the only way to live well.