Why does mega camerupt feel so weak?

I have been trying out trick room mega camerupt and it has been underperforming a lot, heat wave deals little damage while trying to get single KO's with Earth Power feel like too much of a risk when priority aqua jet always OHKO's and the worst of all is I can't run storm drain to try and get rid of this weakness. Should I be using Mega Charizard-Y for my fire type? or am I running the wrong set? or am I doing something wrong?