I am a big believer in the fake-it-til-you-make-it philosophy...but only when it comes to short-term strategies. Getting through a meeting or a rehearsal I haven't properly prepared for. Leading a feedback discussion. That kind of thing. Whenever I know I am engaged in an activity that does not play to my strengths, I embrace the FITYMI way!
But I don't believe it works for Happiness. I think the only way you get there is Honesty and Acceptance.
I am sorry you are hurting. Hugs and strength to you on your journey. Keep your head up and your eyes open, Liz. Rooting for you.