Need tips for carrying

Honestly, as an Amumu main, I go ap or tank and still can't carry. When I do great my top and mid feeds and bot possibly. Like how do I do the most damage on my team as Amumu tank? It makes me so fucking furious that this happens.

http://na.op.gg/summoner/userName=OneMummyBoi

a look at my op.gg and look at the damage charts the end most of time i have close the most damage but I still lose to these terrible players feeding my games.