Minecraft not working sometimes and save and quit freezes the game completely?

I have a Macbook Pro (2014). My Minecraft was working perfectly fine in August. I tried playing it yesterday again and the game had random glitches like no block collection, just blue (nothing being shown). Also sometimes the game is extremely slow.
My main issue is that when I press the 'save and quit' button the game completely freezes and is unresponsive.
My game is completely up to date and so is the OS on my mac.
How can I resolve this issue? I've already spoken to Apple Support but they haven't helped!