I remember when I was 10 years old and I started learning a grammar in school. All these words in grids and tabels... It was so boring! I thought to myself: why I'm forced to fill these gasps and learn rules, while I'm already able to use them correctly in real life? Pointless.
So my advice is: don't try to memorize pronouns, just get corrected while speaking with native!
Pozdrawiam,
Matt