Disappeared animals and villagers, glitching start up of game, white fish, missing minecart chest

Just logged in and EVERYTHING I've worked so hard to gather and tame is gone!!! All my villagers, cats, sheep(I had every colour), wolves, pigs, cows, chickens, my fast horse, my pet fox, my white fish, iron golem, my chest minecart full of all my important rare goodies .... EVERYTHING but my buildings is gone

The game will try and load and the music will start on the main start up screen only for it to glitch and make a weird skipping noise. It also caused my Switch to shut down!!

Fish turn white and grey when you release them and even change names too. They are coloured when you scoop them up but upon release turn white. I spent HOURS finding rare fish only for them to turn white and grey

I also had a minecart with a chest in it disappear full of all my valuable items like my diamonds and name tags

Please I have spent over 130 hours on this world and want all my stuff back please please