Game crashes when Single player gets pressed

My game crashes whenever i hit singleplayer my outputlog says:

Reported exception thrown!
h: mouseClicked event handler
	at cbk.a(SourceFile:433)
	at bxw.a(SourceFile:65)
	at bxw$$Lambda$296/2004952636.invoke(Unknown Source)
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:23)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:2520)
	at bye.a(SourceFile:282)
	at bxu.b(SourceFile:845)
	at bxu.a(SourceFile:381)
	at net.minecraft.client.main.Main.main(SourceFile:141)
Caused by: java.lang.OutOfMemoryError: Java heap space
	at gg.a(SourceFile:56)
	at gj.a(SourceFile:444)
	at gj.a(SourceFile:82)
	at gt.a(SourceFile:119)
	at gt.a(SourceFile:84)
	at gt.a(SourceFile:27)
	at bue.a(SourceFile:92)
	at bue.c(SourceFile:76)
	at bub.b(SourceFile:64)
	at cej.g(SourceFile:35)
	at cej.<init>(SourceFile:27)
	at ceh.c(SourceFile:48)
	at cbk.a(SourceFile:310)
	at bxu.a(SourceFile:728)
	at cbp$4.a(SourceFile:223)
	at byv.mouseClicked(SourceFile:102)
	at bzr.mouseClicked(SourceFile:44)
	at cbp.mouseClicked(SourceFile:507)
	at bxw.b(SourceFile:65)
	at bxw$$Lambda$371/2119716668.run(Unknown Source)
	at cbk.a(SourceFile:428)
	... 9 more