When I open MC Launcher and click "Play", Java window opens and closes immediately. 

This is the error: "The game crashed whilst initializing game
Error: java.lang.OutOfMemoryError: Java heap space".

It's been happening for a couple days. It had never happened to me before, but now it comes up every single time I try to play. I just managed to go on once, and the result was not very good (Esc menu was too laggy, it felt like it would crash every time I clicked on something).

I thought I wasn't allowing much memory, but I think 2GB is enough (I've always had the same for Minecraft, and I'm using no mods or resource packs). These are my JVM arguments: 

-Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M

I'm also attaching the crash report.

Thank you!