Since last update, the program is lagging and shows errors

Since I last updated Illustrator(in the past 2 months, including today), it is lagging with every stroke I try to move around and unite with other points, which I never experienced before and is very irritating because it takes such a long time to finally make my work the way I want it. Also, it is lagging when I have a couple of things that I worked on and I try to copy-paste them on another new file, it creates unnecessary selections that stays on the page and it all becomes black and I can't do anything about it but to close my previous work and work with just a single page. Not to mention that I had lost lost many times a half a day worth of work because is was just frozen all of a sudden, I didn't always saved my work on Drive.