Mac os Mojave issues

I've had problems with league all week, usually it's just slow load times but it's gotten really bad recently. After I updated league it said that I was using an outdated version of mac os. I didn't worry when i noticed that it took me out of low spec mode and just switched it back and I played with some lag. Today I tried to load into league twice and evey time it would stay at a white screen and crash my computer. Now I'm in the low prio que is there any way to fix this?