Crashing every time I get on

Hey I've been trying to create a new world, but every time i try to get on i get this error message, this is also happening when i try to load older worlds or try to get onto a server.

Completely ignored arguments: [--nativeLauncherVersion, 307]
[19:35:44] [Client thread/INFO]: Setting user: fairpaddy1
[19:35:48] [Client thread/INFO]: LWJGL Version: 2.9.4
[19:35:49] [Client thread/INFO]: Reloading ResourceManager: Default
[19:35:50] [Sound Library Loader/INFO]: Starting up SoundSystem...
[19:35:51] [Thread-5/INFO]: Initializing LWJGL OpenAL
[19:35:51] [Thread-5/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
[19:35:56] [Thread-5/INFO]: OpenAL initialized.
[19:35:56] [Sound Library Loader/INFO]: Sound engine started
[19:36:00] [Client thread/INFO]: Created: 1024x512 textures-atlas
[19:36:26] [Client thread/ERROR]: Exception reading C:\Users\patrin\AppData\Roaming\.minecraft\saves\WILL BE MINE\level.dat
java.util.zip.ZipException: Not in GZIP format
	at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:165) ~[?:1.8.0_25]
	at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:79) ~[?:1.8.0_25]
	at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:91) ~[?:1.8.0_25]
	at ed.a(SourceFile:24) ~[1.11.jar:?]
	at bbs.a(SourceFile:83) [1.11.jar:?]
	at bbs.c(SourceFile:67) [1.11.jar:?]
	at bbp.b(SourceFile:58) [1.11.jar:?]
	at bka.e(SourceFile:36) [1.11.jar:?]
	at bka.<init>(SourceFile:29) [1.11.jar:?]
	at bjy.b(SourceFile:42) [1.11.jar:?]
	at bhm.a(SourceFile:367) [1.11.jar:?]
	at beq.a(SourceFile:899) [1.11.jar:?]
	at bht.a(SourceFile:238) [1.11.jar:?]
	at bhm.a(SourceFile:341) [1.11.jar:?]
	at bht.a(SourceFile:502) [1.11.jar:?]
	at bhm.k(SourceFile:404) [1.11.jar:?]
	at bhm.p(SourceFile:381) [1.11.jar:?]
	at beq.t(SourceFile:1583) [1.11.jar:?]
	at beq.av(SourceFile:967) [1.11.jar:?]
	at beq.a(SourceFile:395) [1.11.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.11.jar:?]
[19:36:26] [Client thread/ERROR]: Exception reading C:\Users\patrin\AppData\Roaming\.minecraft\saves\WILL BE MINE\level.dat_old
java.util.zip.ZipException: Not in GZIP format
	at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:165) ~[?:1.8.0_25]
	at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:79) ~[?:1.8.0_25]
	at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:91) ~[?:1.8.0_25]
	at ed.a(SourceFile:24) ~[1.11.jar:?]
	at bbs.a(SourceFile:83) [1.11.jar:?]
	at bbs.c(SourceFile:75) [1.11.jar:?]
	at bbp.b(SourceFile:58) [1.11.jar:?]
	at bka.e(SourceFile:36) [1.11.jar:?]
	at bka.<init>(SourceFile:29) [1.11.jar:?]
	at bjy.b(SourceFile:42) [1.11.jar:?]
	at bhm.a(SourceFile:367) [1.11.jar:?]
	at beq.a(SourceFile:899) [1.11.jar:?]
	at bht.a(SourceFile:238) [1.11.jar:?]
	at bhm.a(SourceFile:341) [1.11.jar:?]
	at bht.a(SourceFile:502) [1.11.jar:?]
	at bhm.k(SourceFile:404) [1.11.jar:?]
	at bhm.p(SourceFile:381) [1.11.jar:?]
	at beq.t(SourceFile:1583) [1.11.jar:?]
	at beq.av(SourceFile:967) [1.11.jar:?]
	at beq.a(SourceFile:395) [1.11.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.11.jar:?]
[19:36:28] [Server thread/INFO]: Starting integrated minecraft server version 1.11
[19:36:28] [Server thread/INFO]: Generating keypair
[19:36:28] [Server thread/INFO]: Preparing start region for level 0
[19:36:29] [Server thread/INFO]: Preparing spawn area: 0%
[19:36:30] [Server thread/INFO]: Preparing spawn area: 5%
[19:36:32] [Server thread/INFO]: Preparing spawn area: 8%
[19:36:33] [Server thread/INFO]: Preparing spawn area: 12%
[19:36:34] [Server thread/INFO]: Preparing spawn area: 15%
[19:36:35] [Server thread/INFO]: Preparing spawn area: 19%
[19:36:36] [Server thread/INFO]: Preparing spawn area: 21%
[19:36:37] [Server thread/INFO]: Preparing spawn area: 27%
[19:36:38] [Server thread/INFO]: Preparing spawn area: 36%
[19:36:39] [Server thread/INFO]: Preparing spawn area: 44%
[19:36:40] [Server thread/INFO]: Preparing spawn area: 53%
[19:36:41] [Server thread/INFO]: Preparing spawn area: 59%
[19:36:42] [Server thread/INFO]: Preparing spawn area: 68%
[19:36:43] [Server thread/INFO]: Preparing spawn area: 75%
[19:36:44] [Server thread/INFO]: Preparing spawn area: 84%
[19:36:45] [Server thread/INFO]: Preparing spawn area: 92%
[19:36:46] [Server thread/INFO]: Changing view distance to 2, from 10
[19:36:48] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 2319ms behind, skipping 46 tick(s)
[19:36:50] [Server thread/INFO]: fairpaddy1[local:E:44e13f8e] logged in with entity id 2053 at (120.5, 68.0, 251.5)
[19:36:50] [Server thread/INFO]: fairpaddy1 joined the game
[19:36:51] [Server thread/INFO]: Saving and pausing game...
[19:36:51] [Server thread/INFO]: Saving chunks for level 'New World'/Overworld
[19:36:53] [Server thread/INFO]: Saving chunks for level 'New World'/Nether
[19:36:53] [Server thread/INFO]: Saving chunks for level 'New World'/The End