Glitching and stucking on load screen

I don't know if this started with the Grim Reaper event or with the switch to DirectX update but my game started lagging terribly. Sometimes I'm stuck on the loading screen for minutes until I close the game from the tool bar. If I manage to make it through the load screen, the gameplay glitches and lags and it getting on my nerves. How can I fix this? Could it be a PC problem? I've been using this laptop for 3+ years and never had a problem like this before in the game so I can only guess it's a game thing.

Thanks in advance!