It sounds like depression to me, I'm depressed and this is literally how my life is organised. Sometimes I can't get things done for days on end, even household chores, but when I've got energy I spend it on getting my work done as tirelessly as I can manage.

Though a lot of neurodivergence and mental illness has overlap with each other, it's a spectrum of behaviours, and it's impossible to actually properly diagnose someone from 150 years ago.