Mod worked on for years totally wiped. Is there any way to recover?

Hi. I have used MCreator on and off for several years making a mod for my friends and I to play with. I tried opening it back up, and with the updated version of MCreator (which it urged me to download) it could not open properly. I tried going to an older version, but it was corrupted and now every mod element is totally deleted. Is there any way to recover??? I am so so so upset and frustrated. I have an old java export of the mod - is there any way for me to re-import that to fix things?