Just my two cents on "fake it till you make it". Another similar expression is "act as if."
To me, neither one implies that you "pretend" that you aren't feeling what you are feeling. It has more to do with practicing a better way of feeling. There's a saying in AA that "You can't think your way into right acting, but you can act your way into right thinking." To me, that means (and I can attest from my own experience that it works for me), that if I wait until I am "feeling it" to do what I need to do, I stay stuck. Because my feelings aren't likely to just change on their own, and WILLING them to change usually doesn't work much better. How many of us cheer up because someone TELLS us to?
OTOH, if I am feeling sorry for myself, or angry, or depressed, but I do something I WOULD do if I WEREN'T swimming in self-pity or anger, like do something helpful to someone else, do something productive for myself, the feeling tends to follow. Not right away, and not every time, but little by little.
I also used those techniques to overcome fear, such as when I tried my first cases in front of a jury or gave my first presentations in my new job. I act AS IF I am confident and competent. The good performance that follows actually helps me BE confident and competent.
I think a lot of the slogans get misunderstood in AA and in Al-Anon. They sound almost ridiculously simplistic and naive, but they are actually shorthand reminders for complex tools that work to get the job done.