Is it true that we actually see everything upside-down?

I've heard this a few times, but I can't wrap my brain around this. So, does that mean when we're sitting upside-down on a couch, that's how things actually look? As in, we're basically on the ceiling and the sky is the ground? I'm so sorry if this is the dumbest thing anyone has ever read, but I just cannot understand this and I feel extremely dumb lol