Ok, I am really mad. This is what happened.

I was playing my SP world. I was putting down doors when the game froze. I thought it might be lag, so I waited. Then it said minecraft crashed. I logged back in and got on my world. I was inside of stone. I soon found out all the blocks I mined were back. Some of my blocks were missing, but I found my pig in a block. No pics because I can only take pics on Multiplayer. Here is the crash:

---- Minecraft Crash Report ----
// I'm sorry, Dave.

Time: 12/21/12 3:49 PM
Description: Ticking memory connection

java.lang.NullPointerException
at ur.f(SourceFile:129)
at ur.h(SourceFile:143)
at qw.a(SourceFile:219)
at px.c_(SourceFile:189)
at qx.r(SourceFile:388)
at qx.c(SourceFile:380)
at md.j_(SourceFile:540)
at qx.j_(SourceFile:200)
at iq.g(SourceFile:175)
at iv.a(SourceFile:199)
at eb.a(SourceFile:136)
at cf.b(SourceFile:55)
at iv.d(SourceFile:57)
at iw.b(SourceFile:39)
at bec.b(SourceFile:84)
at net.minecraft.server.MinecraftServer.r(SourceFile:762)
at net.minecraft.server.MinecraftServer.q(SourceFile:679)
at bdz.q(SourceFile:117)
at net.minecraft.server.MinecraftServer.run(SourceFile:613)
at fy.run(SourceFile:849)

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

– System Details –
Details:
Minecraft Version: 1.4.6
Operating System: Windows Vista (x86) version 6.0
Java Version: 1.7.0_09, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 353325376 bytes (336 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
JVM Flags: 2 total; -Xms512m -Xmx1024m
AABB Pool Size: 1084 (60704 bytes; 0 MB) allocated, 827 (46312 bytes; 0 MB) used
Suspicious classes: No suspicious classes found.
IntCache: cache: 0, tcache: 0, allocated: 1, tallocated: 63
Profiler Position: N/A (disabled)
Vec3 Pool Size: 3269 (183064 bytes; 0 MB) allocated, 1734 (97104 bytes; 0 MB) used
Player Count: 1 / 8; [iq['rigbymad12'/79, l='Rigby's World', x=-261.14, y=53.00, z=-222.51]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.