Suddenly missing chunks and some chunks reverted back to seed

I've been trying out realms for a week now and decided I would go back to survival single player game to work on my masterpiece city and castle.
When I joined the game there seemed to be missloading chunks on my map and thought it to be dome loading glitch that would resolve on its own.
So i walked over the edge of the mirage abyss of missing chunk to realise in horror that I had fallen to my death and lost all my best gear and means of fast locomotion.

As I was reveling in the utter destruction of my lifes work, I respawned 4k blocs away at an unrecognisable seed spawn due to suddenly "missing or obstructed home bed". There, I had my Signature base on 0,0 but everything must have reverted to seed because I couodn't find any trace of the huge structure I had built..
After limping back in peaceful mode for the first time in ever, I managed to snap some screens of the devastated city. Please compare the hideous ones to the nicer builds
Would like a restore of my game somehow...