May be it is because of the stress due to the unpredictability of the income. Writing needs a lot of mental work. May be that is why your sleep pattern changes.
Are you eating healthy and getting enough exercise? Then, try to go to sleep at the same time everyday. I find that while I sleep without a schedule, I am less productive.
I used to sleep during the day. I felt so tires still. Now I try not to sleep during the URL1 makes me feel better and get things done.
Smaller achievements will increase the dopamine level in the brain and will boost your energy level and happiness. A schedule to sleep will be good for you.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.