EA app uninstalled my sims games, can I get my saves back?

@jujuborba  Hopefully you've figured this out by now, but as long as you didn't install your games in the same locations as your save are stored (Documents > Electronic Arts > The Sims _), the saves should be intact.  Uninstalling the game generally doesn't delete saves unless the files are mixed in together.

As for why the EA App uninstalled your other games, where did you install MySims, as in, what was the exact location?  You should be able to see it in the EA App, under MySims > Manage > View properties.