You have to force yourself to confront the anxiety head on. In small doses, gradually and deliberately force yourself to almost be late with something that shouldn't be a big deal but causes anxiety.
Fo that until you start to feel less anxious about it. Next step is to deliberately be late with something.
There is more to it than this, but this is the short version. Read up on it, it is what they do for PTSD.
Feeling guilt or shame in response to your thoughts about not doing the task right then?
You don't need rest to not go insane. That's a limited mindset. Instead, think of your work as building momentum. You did a lot today? Tomorrow you can do it faster.
Are you procrastinating or avoiding working?
Community for individuals with anxiety for exchange and helping each other.
This is a non-judgemental community and everyone is welcome as long as you apply to the TOS and follow basic etiquette.
No -isms, just be nice.
Keep in mind that this does not equal an exchange with a medical/mental health professional.