Chances are they’re gone. I didn’t re-make my theme, I just played with the default blue last night, and when I logged in today I got my custom maroon theme back. When you made that temporary theme it likely overwrote the file storing your old ones.
If you run your computer on something like ZFS or btrfs with regularly scheduled snapshots you could recover the themes by overwriting the EVE config folder with the one from your snapshot, but since you’re on a mac you’re probably just going to have to recreate them from scratch.