I have lost my level progress twice

Hello, I need help with an issue that effecting my play of borderlands 3. I have lost levels for my FL4K character twice. Once from level 53-50 then from level 57-50. I lost all of the loot and skins I spent forever grinding. It is ruining my experience and I just want to have fun playing my favorite game. I was told to ask here to see if I could find help here. Any help on the issue would be greatly appreciated. Thank you all who help, take care.