Cydia Might Be Slow or Unresponsive, But It’s OK
Unfortunately, there isn’t much you can do. The only solution is to wait for things to calm down. I suspect that in a day or two, most jailbreakers will have already installed the untether, and things will start going back to normal.
So be patient! In the meantime, you may want to try using Cydia late at night when there is less online activity.