Are you playing on the paid version or Free version? The free version doesn't have saving and does not save progress.
Other than that, saving is disabled during the Cum Trials. If you use an item such as the Emergency Teleported item that is used in case of softlocks while inside, your saves will become locked until you re-enter normally. You need to exit the cum trials the normal way to avoid this. This is why items such as the Emergency teleporter must be used only on emergencies.
I really wish I could figure this one out. As a last case remedy, check if the game you are opening the same one, maybe you have more than one version on Itchio, and you opened a different one after the crash. If not, check if itchio downloaded an update while you played which caused the crash and overwrote the saves. Other than that, I can't really think on what could cause this. I am very sorry.