failure anxiety really is psychological torture
you can't bring yourself to start any task because of the possibility that you'll fail to produce anything of value and end up not only having to confront the fact that you were never capable of doing it, but that you wasted time and energy trying. but every second you don't spend working on it your brain is screaming at you that you're losing valuable time and only increasing the probability of failure.
and every success you've had in the past does nothing to reduce your anxiety, and in fact only makes it worse, because you feel like you've given other people expectations of you that are impossible to meet, since as far as you're concerned all your previous achievements are the result of chance and not your abilities and skills.