Today I finish my book :D!!!
It's called Productivity bomb and it's a book that teaches you how to become a productive person. I face my self this problems to be productive and I know how hard it is. Especially when you are working on side projects where there are no real side effects if you just don't do it.
The book is completely free and really small (45 minutes read).
https://imcarlos.pro/book/
It's available in Portuguese and English. There must be some problems with both versions but maybe can help you.
Thank you