I lost all of my Stuff In my Inventory When i Left My Computer Afk Fish overnight

I lost literally all of my stufff in my inventory. I woke up and came to my computer and i saw it had disconnected. Then i started the server and i spawned as a Alex Skin. Even Tho when i go to other servers i spawn as my normal skin. I dont even have moderator on the server anymore and my account is not even cracked. what should i do can you like go back few saves or something.