I can really relate to what you're saying, although I don't have the answers...but if my T told me to just do it, I think I might laugh. It reminds me of that MAD TV sketch when the therapist tells the client to "just stop it!"
It is so impractical and if I could just do it, I would. I had a session last night and shared my frustration with my T. I was like, so if I just stop controlling and try to "just be" (which is so abstract to me) then my mind goes to trying to come up with steps and how tos to just be...which ultimately, leads me back to performing! Totally counterproductive. My T tried to lead me to thinking about what it might be like to just be and not pressuring myself to perform...and after a visualization exercise I actually freaked out....so I think he's trying to get behind what keeps me from finding worth in myself for who I am rather than what I do and there's a whole lot more there than I thought...
Sorry - I'm really not sure how to solve this issue as I'm a major perfectionist as well. Just know you're not alone