scared to start this big book

Books like these used to be normal for me. 'A bit of light reading' as Hermoine would've said. Since my burnout my possibility to concentrate had dropped to very low levels. I couldn't read books anymore, I had to focus too long. I have been reading some pockets last few months. Being able to to that felt like victory. But I ran out of pockets, so I borrowed a book from a friend. It has been lying around here for over a week now. But it looks very intimidating, such a big book. And I don't dare to start reading it.
Books never felt like that for me.