League won't let me log on, and it keeps crashing my game. Please help.

I don't know if this is a 'bug' but i'm putting it in this section anyways cause theres no "Help" options.

Normally my League starts crashing whenever my MacBook air needs to be updated. And when I update the crashes usually go away. It's very very very rare that I lag or crash in a league game.

However today when I logged on it didn't accept my password, even after I changed it three times. I know my password is correct yet it took me nearly 10 mins to log on. And in the second game with my friends I kept crashing all the time, my FPS and Ping were going haywire which usually never happens. I usually get a constant FPS and Ping that doesn't cause me to lag at all or crash. Nobody in my house is downloading anything and my wifi network rarely if ever makes me lag or crash. However since the last two updates to the game i'v been lagging more, and now I'm crashing every 5-10 minutes or so. I cannot play properly when I'm constantly crashing like this.

If anybody can help me that would be great. I HATE crashing, even if I crash once it can ruin the entire game for me since I get behind. Especially when I play mid or support. It's driving me mad that I can't log on even when my username and password are correct cause i've changed them both about three times.

I have a MacBook air and I'm using High Sierra.

I don't know why all of this is happening but i've tried to log back in and it's not letting me. So if anybody can help that would be great. And My laptop doesn't have the space to download virus filled Mac/windows replacements. League worked FINE on my mac up until now, I'm not going to download anything I don't know is legit or helpful.