Lost Server

This morning, I went to go on my Sky Factory 3 server to play with my friend and it wouldn't let either of us join. It kept saying there were missing blocks in the world. I then downloaded the world and opened it in single player and all of the blocks in the world were replaced with different items from the game. (Ex. the blank runes in my blood alter was replaced with liquid blood, my giant chest was replaced with chisel and bits blocks, and there was no sand in the world) I really hope there's something I can do to get my island back. I worked for months on it and I don't want all of that progress lost.