My consumption has been higher than usual lately too, but not to your extent - mostly due to WFP mode not working at the moment (FFXIV - JP Elemental Servers - #10 by weongyo a MF admin said this post will be updated when its running again, when it does, enable it).
Try checking if Full VPN mode is enabled, if it is, disable it. And if possible don’t start MF while there’s a patch to be downloaded (both official launcher or dalamud launcher if you use that). You can click ‘Connect’ on Mudfish while in the game title menu before clicking ‘Start’ to get into character selection.
Hope this helps!