If you’ve ruled out mental causes (like perhaps ADHD, as discussed in other comments) then perhaps it’s something about the work. I’ve often found in these per

If you’ve ruled out mental causes (like perhaps ADHD, as discussed in other comments) then perhaps it’s something about the work. I’ve often found in these periods that there’s some underlying part of the work that makes me not want to do it, usually that subconsciously I’ve categorised it as being pointless. It might be worth brainstorming the nature of the work itself rather than blaming yourself.