Insomnia and depression. Sleeping!

Hi Doctor, I'm suffering from difficulty in sleeping since about 3 weeks and I've not slept at all in some days. It will started with 1 sleepless night which was not a concern. But after that everyday it is causing anxiety and I began to worry how will I sleep tonight. Even though I got sleep that night, still next day I'll worry about how will it happen tonight etc.. Every time I go to bed various thoughts start coming to mind and keep my awake, which in turn makes me lot tired next day. I've lost interest in everything else which I used to enjoy before 3 weeks and always the same thing keeps going on in my head worrying about sleep. My family doctor has now prescribed etizolam 0.5mg every night before sleeping. It helps a bit to get about 4-5 hours of sleep but not much. How should I break this cycle of insomnia and depression. I'm only 23 now. Please advise how can I stop constantly worrying about it and stop these thoughts from coming during sleeping