I can only say that it not "up to your mind to overcome your fear". Phobias are not that easily overcome.
I do not understand why you want to do this thing when it is cleary a problem, but that is your choice. I just want to say that if it does not work, I hope you will not blame anyone - not your Master and certainly not yourself. There will always be things we can do and things we cannot do - no one can do it all and no one is less a sub for that.