Game froze and changed the map

I was playing Minecraft on my switch last night and while I was in the middle of killing a chicken the game froze and the entire map is completely different now my house that I had been working on is completely gone I have went around in a circle for the past 5 hours around where my house was on the map and it's nothing but ocean now when it used to be snowy mountains I'm quite upset because I had alot of things onside of this home I had built and now I can't get it back please help