NEW update and total NOT satisfied! lost my whole save!

Since a couple seconds ago it totally messed up my game laptop  and got a terrible lag which does the controls doesnt give a good control of the character.

i was playing Hard mode on a private game.
and that totaly screwed it up!
loading the area takes forever, and those hostile vilager mobs are messed up!
I blocked with my shield and with 1 hit i got killed?!
this was no problem the patch before!?

How can i get back my last save? :/