It all started when I took a boat ride, then suddenly the game crashed Tesselating liquid the in world. After that I went on land then a Creeper exploded and then the game crashed for the same reason. Here's the crash report.

---- Minecraft Crash Report ----
// Would you like a cupcake?

Time: 2/7/19 1:42 PM
Description: Tesselating liquid in world

java.lang.NullPointerException: Tesselating liquid in world
at dfc.b(SourceFile:15)
at dfc.a(SourceFile:27)
at dfc.c(SourceFile:46)
at dgf.a(SourceFile:64)
at dge.a(SourceFile:78)
at dig.b(SourceFile:208)
at did.a(SourceFile:88)
at did.run(SourceFile:41)
at java.lang.Thread.run(Thread.java:745)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

– Head –
Thread: Client thread
Stacktrace:
at dfc.b(SourceFile:15)
at dfc.a(SourceFile:27)
at dfc.c(SourceFile:46)
at dgf.a(SourceFile:64)

– Block being tesselated –
Details:
Block location: World: (-1136,48,240), Chunk: (at 0,3,0 in -71,15; contains blocks -1136,0,240 to -1121,255,255), Region: (-3,0; contains chunks -96,0 to -65,31, blocks -1536,0,0 to -1025,255,511)
Stacktrace:
at dge.a(SourceFile:78)

– Affected level –
Details:
Level name: MpServer
All players: 1 total; [dex['Eligaming363746'/97, l='MpServer', x=-998.92, y=62.07, z=272.60]]
Chunk stats: MultiplayerChunkCache: 625, 425
Level seed: 0
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options: {}
Level spawn location: World: (208,66,18), Chunk: (at 0,4,2 in 13,1; contains blocks 208,0,16 to 223,255,31), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 647435 game time, 12341 day time
Level dimension: 0
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Server brand: vanilla
Server type: Integrated singleplayer server
Stacktrace:
at dcm.a(SourceFile:466)
at cqg.b(SourceFile:1877)
at did.run(SourceFile:47)
at java.lang.Thread.run(Thread.java:745)

– System Details –
Details:
Minecraft Version: 19w06a
Operating System: Mac OS X (x86_64) version 10.12.6
Java Version: 1.8.0_74, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 650519040 bytes (620 MB) / 2080374784 bytes (1984 MB) up to 2147483648 bytes (2048 MB)
JVM Flags: 8 total; -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
Launched Version: 19w06a
LWJGL: 3.2.1 build 12
OpenGL: NO CONTEXT
GL Caps: Using GL 1.3 multitexturing.
Using GL 1.3 texture combiners.
Using framebuffer objects because ARB_framebuffer_object is supported and separate blending is supported.
Shaders are available because OpenGL 2.1 is supported.
VBOs are available because OpenGL 1.5 is supported.

Using VBOs: Yes
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs:
Current Language: English (Canada)
CPU: 4x Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz