Feeling sensations of a panic attack

Hi! I have a performance tomorrow and have felt some feelings of fear come up around it. One time, before a big performance event, I had a very long, uncomfortable, intense panic attack beforehand.
Some of those same physical sensations showed up in my body today.
I’ve identified that one of the thoughts that contribute to this is “I can’t mess up.” So I’m practicing believing it is ok if I mess up, and do believe that, it is not such a big deal if I mess up.
Another thought that contributes to the feeling of fear and the physical sensations associated with a panic attack are, “I can’t have a panic attack. I can’t freak out.”
So, I’m trying to tell myself that it is ok if my body starts to feel those sensations. That my brain is just trying to protect me. I can have compassion for myself.

If I’m really being honest though, my motive for telling myself it is OK to have a panic attack, is simply to trick my brain/body to relax so that I DON’T have a panic attack, because that level of pain and discomfort is not something I ever want to go through again! I am ok with experiencing the feeling “Fear”, but when the body starts to freak out and I’m in lots of physical discomfort… I really would prefer not to experience that.

Can you help me?