This site has a table which helped me a lot remembering the declension. :) https://deutsch.lingolia.com/en/grammar/pronouns/declension/genitive

The *personal pronoun* genetive forms are "meiner" etc. You use them when the sentence requires a genetive object: sich etwas (Gen) erinnern -> Ich erinnere mich deiner. The *possessive pronoun* forms that are used to modify another noun are "mein" etc.: Mein Auto ist rot. However, if you omit the noun, and want to use the possesive pronoun on it's own as a substitute, you use the same form as the personal pronoun genitive: Mein Auto ist rot. Dein Auto ist blau. -> Meines ist rot. Deines ist blau. It's more or less the same in English: My car is red -> Mine is red. He's not a friend of mine (personal pronoun).

English has "my" and "mine" too, no? ;-)