It took me over 10 years to overcome this. For the longest time, I needed fatigue to kick in to overwhelm the anxiety and enable productivity (albeit at nowhere near my potential).
This made me laugh. So relatable! Sometimes I spend my first 2 hours in bed plus having a very long breakfast with my wife (I work remotely) just so I can mentally prepare for the work ahead.
FWIW, the resolution for me eventually came when I was able to get a nice feedback loop of breaking off what I thought was a day’s work at the beginning of the day, doing a day’s work, and either succeeding or taking the loss and rescoping for the next day. The sleep deprivation is a cycle from hell, where I can get something done, but it’s at a cost of the next 2 days of productivity, which causes more anxiety...