How can I have reputation change greater than my reputation?
What is the "change" field even for?
The "+3579" in your screenshot is the change in rank, not the change in reputation. Therefore, prior to the last "tick" of the list (I think in that case it's weekly), your rank was around 4.5k - you have moved up 3579 ranks to the new rank of 1080.
The reputation change is only shown with the "week reputation" column and the such.