Game Disconnects during loading screen...

Sooo basically after champ select I go into the loading screen waiting for the game to start. Then when it reached 100% it immediately disconnected me and I had to force stop the game and restart the client and now I'm minutes and minutes late into the game. This has happened many, many times and I'm not sure if it's a problem with my computer or its the server's fault but every time this has happened I'm on really good wifi. Please help, thanks :)