Big of the new nether update

I was in the new nether update mining app here and my power went off then I logged in back and most of the blocked were not there in the nether I can't explained it that good but then I killed my self in the game to get back but I had good stuff so then I went back to the nether to get my stuff and when I enters the nether the pordal was not there any more not even the stuff I billeted  so I could not get my stuff it was like it was never touched and still some big chunk of blocks  were not there please help I worked hard on my world and now I died with it all of my stuff .I don't want that to happen to other people thank you