Ah, you reminded me that I haven't put a save build feature in Hybrid yet 😅 usually to get around how hostile the Twine language I use is to long term saves (since people clear their cookies fairly often) I put in a feature that lets you start from whatever chapter in the game you want, and set all relevant characteristics manually. I'll need to add that!
Until then, like necrosian said, save files DO exist in the browser. The next version of the game will let you choose where to start, though, so I wouldn't worry too much about losing that content!