Half of the things I built are my world are gone

I loaded my world after the most recent snapshot and the walls doors, fences alot of things wre missing. I spent 6 months building that world and Im very upset about this. I tried logging in on my user name and snapshots but both were currupted.

User Name: shasta2024
login email: nascarfan2024@ymail.com
Contact email: shasta2024@aol.com