Upon reflection (sometimes I get to that point sooner, sometimes later) the problem is usually that the task is too vaguely defined to start working on it.
I ended up just doing something, anything, even if it's wrong. Then I could correct it and do it properly. But sitting there fretting about it being hard and vague wasn't making any progress
I was promoted to a team lead position in Autumn of 2019. Things went well, if hectic and stressful, for the first couple of months. But the slower period in December really did a number on my motivation and focus, and my anxiety kicked in big time.
Now I have a huge problem doing actual work, and so often get distracted into spending hours on technical, interesting tasks that aren't work related. It doesn't help that I have a million different interesting projects that I'd like to mess around with.
And the work to-do list gets longer, and longer. And my anxiety gets worse and worse.
I hope you find a solution to your issues. Good luck!
With other things, usually it’s best to run to google, or send an email to your boss or professor, or just pull out a notepad and start jotting things down. Sometimes it also helps to take a quick break - exercise, take a shower, etc - and then come back.
Although the irony is that I’m typing this comment out as a form of procrastination when I should be pulling out my laptop to do some remote work...
Anxiety can be measured, your body segregates hormones in order to change the state of your entire body in order to prepare for this danger.
Unfortunately danger for primitive humans are different than current society dangers. It usually prepares you either for a fight or a flight (running away as fast as possible).
If you get too anxious for example fighting for your life or your children, you can break your bones and don't feel pain.
But this natural response is of no help if you feel that you will lose your job, or break your relationship...
In fact some work can't be done at all under these hormones influence, like intellectual work. Your body prepares you for action, not for reflexion.
Realizing that really helped.