Some days, it's easy to move forward. You have a string of decent days where your doubt isn't overtaking you, and things are somewhat moving along.
Then you wake up one morning and everything is wrong. How you feel, your worth, our mentality. And you have to fight it. It causes you to have trouble breathing and focusing. And you're not quite sure how you'll get through the day, so you try to ask for help.
And that fails miserably, since it feels like what you're getting for feedback is to suck it up and you're being yelled at. You react and lash out because that feedback caused you more doubt and pain.
And because of that lashing out, it causes further pain because you get yelled at. And it's not the kind of yelling where you're angry and ready to defend or retort. It's the kind of yelling you just take. It's the kind that reminds you of how horrible you are and your failures and what you did wrong.
It makes you shrink away, not knowing what else to say, except 'sorry'. It's the kind of reaction that reminds you why you are supposed to strive for perfection and when you fall short, it makes everything wrong and diminishes your self-worth.
It reminds you of how alone you really are. It causes you to be paralyzed. It causes you to further question your existence and reminds you that you're not good enough.
And it gives you the perfect excuse to go to bed early and hope for a better day tomorrow.