One of our games was making very similar numbers for about 4 months, then a competitor, a talented college kid, decided he would make a game really similar to ours and put it out there for free. Not even with ads.
Over the next 4 months, we saw sales drop to about 1/5 of what we were making in our good months. He has out-ranked us and doesn't seem to have any interest in making much money tho he as since put in an ad that shows up upon a game-over.
I'm worried that you just put a nail in your own coffin, and are about a month or 2 from realizing it... on Android at least.
I wish you good luck. You need to step up your game now and make sure you are on the very cutting edge. If there's even 1 feature that your users want that you haven't done yet, that's the one feature that gets the competition an edge-in on your app.
From my experience most successful entrepreneurs don't worry about competitors that much. They just focus on building the absolute best product they can.