Why doesn't caffeine affect me?

I know I don't have a tolerance to it because it's never really woken me up, so therefore I never saw any point in consuming it a lot. But yesterday, and to see if this was still the case, I without any exaggeration: drank 6 cups of strong coffee, 2 redbull, and 2 excedrin - all within about a half hour. And literally experienced no effects whatsoever; no jitters, no energy, and no resulting crash - just nothing. like I hadn't even consumed any of that stuff at all. I could've gone back to bed if I wanted to haha. I don't get it?! :(