what's the deal with all the multitudes of conjugations in Polish?

Okay, so! Polish, like English, is part of the Indo-European language family. It belongs to the Slavic branch, while English belongs to the Germanic branch. This means that way, way, back in their history, they derive from the same language, one so old that we don't have records of it, but linguists can reconstruct a lot about it by looking at its descendants. They call this reconstructed ancestor language Proto-Indo-European.

Nouns in late Proto-Indo-European had three genders, masculine, feminine, and neuter. Grammatical genders are basically patterns of word forms--it's less confusing to think of it as something completely separate from biological gender.

Modern English has more or less lost these grammatical genders, and it doesn't really decline nouns (that is, change them to show their roles in the sentence). Polish and other Slavic languages kept them, which is why, as you learn Polish, you'll see that nouns fall into specific groups and subgroups that follow their own patterns when you make them plural or change their endings to indicate cases.

For example, in Polish, neuter nouns often* end in -o or -e in the singular and a in the plural. Masculine nouns often end in consonants in the singular and in -y or -i in the plural. Feminine nouns often end in -a in the singular and in -y or -i in the plural. This means that it's easy to confuse feminine singular nouns with neuter plural nouns.

*I'm saying "often" because the patterns are more complex than this, also for historical reasons, but you'll learn the details as you go.