Updated to OS X Yosemite on MacBook, can't even log into LoL

I am not very good with computers and how to fix problems so I try to Google my way through. I've been reading forums and other websites, but it seems like most people are able to at least get into League, even though they some problems here and there, while I can't get past the login screen. I have a MacBook Pro 13" and I bought it on May 2013. I'm using my college internet, not ethernet.

What shows up is:

• "Remember Username", "Disable Login Music", and "Disable Menu Animations" boxes get unchecked every time I open LoL, even though I've been checking those boxes.
• "Logging on..." for about a minute
• "Connection Failure - Unable to connect to the PvP.net server"

What I've done is:

• Log in and log out again and again.
• Before clicking "LAUNCH", I went to settings and clicked "Repair".
• I uninstalled and reinstalled League and repeated the top two things.

I don't have a backup drive thing for Time Machine, so I don't think I can really downgrade to Maverick...? I don't know what to do ;___;