WOW.... I almost had an orgasm reading all your MAC goodies! LOL!!!
Anywho, you should try to do some swapping maybe? But honestly, try to stop buying makeup and re-assess what you already have... I have the same problem - hoarding tons and tons of makeup...not just makeup, but clothes and shoes as well. For me, it's somewhat of a sickness. I am trying to become more of a simple "minimalist" in my old age...lol... but it just ain't happening. The problem is, though, like you, I feel too overwhelmed from what I DO have and it becomes chaotic and "not fun" anymore.
Get re-acquainted with all of your lovely MAC products.. maybe re-arrange your collection, clean up the containers... do whatever it takes to make them feel like new again.
HTH.