Often when I have something to get done, I can’t get myself started for a few days. Even if the week before I was very productive.
I used to get upset about it, but then I realized that such a wave pattern is perfectly normal.
When you do different things: pet projects, open source, freelance and non-programming-hobbies; life became richer. I have noticed that drops in some areas are followed by rises in other areas. If I decide to work on a freelance project but feel that I need to edit photos then I’ll edit photos. I know I’ll be back to freelance soon. (Indeed it limits projects I can work on but the most interesting ones remain.)
Good example of this is GitHub profile: you can see a rise, a drop and the beginning of a new rise: