level.dat deleted after crash

It seems I can't play my world anymore. I had entered a nether portal and found a zombie. But when I struck him the game crashed. I repeated this only for the game to crash again. At this point, I could no longer access the world. I checked the saves folder and it was still there, but the level.dat file had mysteriously disappeared.

Description: Exception generating new chunk

java.util.concurrent.ExecutionException: java.lang.RuntimeException: Tried to load a block entity at a wrong location. ec{x=211, y=56, z=161}
	at java.util.concurrent.CompletableFuture.reportGet(Unknown Source)
	at java.util.concurrent.CompletableFuture.get(Unknown Source)
	at rw.c(SourceFile:129)
	at sd.a(SourceFile:84)
	at se.c(SourceFile:143)
	at rx.k_(SourceFile:219)
	at net.minecraft.server.MinecraftServer.w(SourceFile:694)
	at net.minecraft.server.MinecraftServer.v(SourceFile:627)
	at cxd.v(SourceFile:155)
	at net.minecraft.server.MinecraftServer.run(SourceFile:532)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.RuntimeException: Tried to load a block entity at a wrong location. ec{x=211, y=56, z=161}
	at bhs.B(SourceFile:1093)
	at bhs.G(SourceFile:1148)
	at ru.a(SourceFile:33)
	at ru.put(SourceFile:11)
	at it.unimi.dsi.fastutil.longs.Long2ObjectMaps$SynchronizedMap.put(Long2ObjectMaps.java:371)
	at rw.a(SourceFile:207)
	at java.util.concurrent.CompletableFuture.uniApply(Unknown Source)
	at java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.util.concurrent.CompletableFuture.postComplete(Unknown Source)
	at java.util.concurrent.CompletableFuture.postFire(Unknown Source)
	at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source)
	at java.util.concurrent.CompletableFuture$Completion.exec(Unknown Source)
	at java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source)
	at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
	at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)