Perfectionism is so tough. It sets us up for constant failure, because we are so rarely perfect. Sometimes "good enough" is "good enough" and sometimes others don't even realize that we aren't perfect because they don't really see the difference between the "good enough" and perfect.
I relate to feeling like you have to put on an act at work. I fall into the trap of feeling like I have to seem happy, competent, and in control. It's really hard when you just want to curl up in a ball and cry. I actually took leave from work a few months ago for 3 weeks. That was huge for me.
I understand if you don't want to talk about your depression with your boss, but maybe you can make a meeting as just talk about feeling overloaded with work? Maybe mention that at least for the near future you need to have your load lightened.