You’re clearly not happy @avenueaspirr - your lashing out at other posters seems like a projection of your anger with yourself. But you have to ask yourself how productive being angry is for you. Does it make you feel better or does it just make you feel more shit?
If it’s a system error have you escalated this via your manager to IT support? I know how impotently raging some corporate systems can be (don’t get me started on MS Appointment and Calendar apps).
But there’s clearly a problem if your manager is asking you about productivity. She’s doing her job, as tough as that is for you. If it’s a new system maybe you need some more training?
However, by refusing to participate in a screen sharing you are rather colluding with the view -as erroneous as you say it is- that you are not working as effectively as you might. Whatever the truth of the matter (and it’s likely that neither you nor she is either completely wrong or completely right) by refusing to participate you’re backing yourself into a corner.
Your reaction has the potential simply to cement the view your manager has of your productivity and - more importantly - to entrench your self-image of yourself as shit.
Your self-flagellating post is quite disturbing - you’re catastrophic if and thinking in really black and white terms. It sounds very damaging.
Maybe you could approach this whole thing differently? What’s really at stake here is the way you think about yourself. So if you feel you’re in a shit job, doing it badly, are there other things in your life which give you a sense of accomplishment or satisfaction or even joy? What could you do to maximise that part of your life and look after yourself?
No need to answer these questions but you seem in a pretty bad place, and I suspect it’s not just caused by this situation at work. That seems to be a symptom rather than a cause.