Insomnia Support Group
Insomnia is a symptom, rather than a disease, and is characterized by inadequate quantity or quality of sleep. People with insomnia complain of difficulty falling or staying asleep, which results in significant impairment of daytime functioning. Insomnia is categorized as transient (shorter than one week), short-term (one to three weeks) or chronic (longer than three...

The power of your mind to control your body should not be underestimated. On a physiologic level, the worry and stress you feel about the idea of sleep produces neurotransmitters and other substances that make sleep more difficult.
You are creating a vicious self-perpetuating cycle from which it can be difficult to escape.
Fortunately, there is a way out. It's called cognitive restructuring. It enables you to do the opposite of what you're doing now.