Weird how a simple tiny game with nothing heavy make your computer out of memory just trying to load the save game.
Not necessarily computer. I had a post around here somewhere (edit:
found it) mentioning how there are limits enforced by the
browser that even hamper your ability to save since the space "allowed" remains constant while your savegames naturally grow as you play, so you end up with fewer save slots the longer your playthrough. As for memory consumption of the game tab itself: highest I have seen was close to 2GB, but anything 1.5GB and above meant I would be seeing "tab not responding: wait/close" every time I end a day. Just a nerd-but-not-really moment about how your system as a whole is fine.
If you still have those saves in your browser - did you try exporting them, deleting all saves from the browser, and then re-importing the saves?