I used to expertly discount my accomplishments and inflate my shortcomings. For too long I operated under the banner of "don't rest when you're tired; rest when the job is done". It took a long time to disengage with. Therapy helped. I learned to recognize the signals I need rest – and to allow myself to do so. Counterintuitively, I experienced a net increase in quality output once I got better at it.
Anxiety stems from thoughts of the future. But there's no point. It's unknowable and we have little control over outcomes. The ideal version of ourselves we create inhabits the future; it is, by design, unapproachable. And tyrannical. Always reminding us that we "should" be doing this or that.
I try and find fulfilment in doing that which I succeed in DOING. It's enough. Beating myself up over the inverse – the imagined, endless possibilities – is nonsense.