I am able to see the Minecraft Launcher, and when I click play it loads as normal. But when it shows the Mojang screen (the screen before it shows play and minecraft realms and stuff), it gets stuck there. Then it crashes. And here is a copy of the crash report:
---- Minecraft Crash Report ----
// Don't be sad, have a hug! <3

Time: 3/20/15 1:50 PM
Description: Initializing game

java.lang.OutOfMemoryError: Java heap space
at bmj.a(SourceFile:230)
at bmi.b(SourceFile:130)
at bmi.a(SourceFile:77)
at bou.j(SourceFile:553)
at bou.a(SourceFile:139)
at bov.a(SourceFile:23)
at bno.a(SourceFile:99)
at avf.am(SourceFile:448)
at avf.a(SourceFile:310)
at net.minecraft.client.main.Main.main(SourceFile:124)

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

– Head –
Stacktrace:
at bmj.a(SourceFile:230)
at bmi.b(SourceFile:130)
at bmi.a(SourceFile:77)
at bou.j(SourceFile:553)
at bou.a(SourceFile:139)
at bov.a(SourceFile:23)
at bno.a(SourceFile:99)
at avf.am(SourceFile:448)

– Initialization –
Details:
Stacktrace:
at avf.a(SourceFile:310)
at net.minecraft.client.main.Main.main(SourceFile:124)

– System Details –
Details:
Minecraft Version: 1.8.3
Operating System: Mac OS X (x86_64) version 10.9.5
CPU: 4x Intel(R) Core(TM) i5-4260U CPU @ 1.40GHz
Java Version: 1.6.0_65, Apple Inc.
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
Memory: 357800 bytes (0 MB) / 1060372480 bytes (1011 MB) up to 1060372480 bytes (1011 MB)
JVM Flags: 5 total; -Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
Launched Version: 1.8.3
LWJGL: 2.9.2
OpenGL: Intel HD Graphics 5000 OpenGL Engine GL version 2.1 INTEL-8.28.32, Intel Inc.
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: No
Is Modded: Probably not. Jar signature remains and client brand is untouched.
Type: Client (map_client.txt)
Resource Packs: [Sphax PureBDcraft 512x MC18]
Current Language: English (US)
Profiler Position: N/A (disabled)