Why??

Its 02:00am and I am not able to sleep. This sleeplessness is making me sick for more than 2 weeks now. I am tired and sleepy yet my brain isn't stopping. I don't know how to just stop my brain, make them calm and go to deep sleep.

Why ain't I able to sleep?
Why my brain is not calming down?
Why am I thinking so much of work?
Why am I thinking so much of the uncertainties of life?
Why do I have to think of all the daily life requirements?
When did I sign-up for all these tensions?
When did I grow up to think all this?
Why did I leave home?
Why am I writing this now?
Why did I ever grow up?

These are some of the questions popping up in my little head. I don't know how and why the complex nervous system works to think all this.. Probably because I am nervous and anxious for my PhD as this is the last year and I need results to finish it.. do I have a high achievement level and expect too much from myself??.. Or I am uncertain about the future of my personal life, if I will ever be able to live my life with the person I want to grow old with.. Or I am just thinking of my responsibilities towards the people I love and care.. or I am just nostalgic and miss my old life with my family where I didn't have to take care of anything.. probably I want to live that life again.... to depend on someone for certain things, just not to think about daily life requirements.. and not have the need to take decisions on my own... I want to be a kid again.. I don't want any responsibilities any tensions any duties.. I just want to live peacefully.. and sleep quietly...