Not trying to write a sob story or looking for pit or anything, but I'm autistic and have co-morbid anxiety, depression and OCD which I've been struggling with for pretty much my entire life. Most of the time, the reason I procrastinate is because I'm going through a particularly bad spell of depression and I basically can't bring myself to do anything. When that happens, it's not unusual for me to not be able to write for extended periods of time.