says The game crashed whilst unexpected error

When trying to go to my Realms, it says:
The game crashed whilst unexpected error
Error: java.lang.NoSuchFieldError: currentDimension

It also says it looks like you are using a modified version of Minecraft. The only version I have is the one I bought through Mojang, and it updates itself. I have mods, yes

PLEASE tell me what to do to fix it, I NEED my Minecraft daily fix!

Thanks!