Transitioning from PC to Mac

Hey! So I'm a very big Sims 4 player and I just transitioned from my PC to using exclusively my Macbook air. When I went to download the sims 4 it said it was "only for windows" so I downloaded EA and downloaded the Sims 4 base game. I now realize that my extension packs are ALL gone even though I have been using them forever. I wasn't going to use all of the extension packs possibly just one or two but I was surprised that it says I only have the base game as I don't want to spend the money to repay for all of these extension packs. ANY advice will be helpful since I have no clue what to do.