Cleaning my desk or going through my inbox instead of doing whatever needs to be done is just my brain cargo-culting "working at a computer in an office", not unlike a toddler imitating grown-ups. At this point it's very useful to train yourself to talk to somebody about what you need to do, or write a list of the steps you need to take and keep breaking it into smaller parts, until you find it's easier to do what you were about to write than to write it.
It's a classic trick, I call it "starting with a corner", from when you were a child and you had to color the entire background with blue -- it was so off-putting, even if you knew /how/ to do it, it was so much work. But if you start with a corner, at least you got somewhere.