Make a list every day of the things you did correctly that day, including the most mundane shit you can think of like 'I turned the washing machine on' or 'I went to work at the correct time and in the correct place'. Read the previous entries every few days and whenever you feel worthless. You probably have a tendency to overthink everything and rely on other people for assurance that you're not a total fuckup, so this is a good way to remind yourself that you can do things and give you a better idea of how capable you actually are. CBT is good, there are workbooks and worksheets online that you can use if therapy isn't available to you right now.
And remember that other people are not your mother. They won't be obsessing over your actions like she did. If you say something stupid to the barista when you're ordering your coffee, they won't give a single shit, they see worse things every day. If you forget to attach files to an email, you won't be the laughing stock of the office, everyone does that sometimes and you just send another email with the files attached and an apology for forgetting to attach them the first time round. People truly don't care about your shortcomings. Change your language to be more positive, there are a lot of resources online about this, it's things like saying 'Thank you for being patient with me' instead of 'Sorry I need your help' and it really does make a difference.
Be careful not to latch onto anyone who gives you positive attention. Remember to never, ever base your self worth on anyone other than yourself.