Right? I didn’t know until relatively recently they’re considered a third kingdom: flora, fauna, funga.

Animals are more closely related to fungi than we are to plants. Our closest shared ancestors were likely these little guys: https://en.m.wikipedia.org/wiki/Choanoflagellate

Source: I took Bio 101 last semester so I'm pretty much an expert now.

I think protists (like the amoeba) are considered a fourth kingdom within the eukaryotes. But that isn't even the highest level of classification: eukaryotes are only one of three domains of life, the other two being bacteria and archaea. (Eukaryotes are believed to have originated as symbiotic unions of ancestors of archaea and bacteria.)

It's more like animals, fungi and plants are weird colonial protists.

And the fourth kingdom that are neither plants, animals, nor fungus: Protista. The "animalgae"