Facebook Ads Lowering Organic Reach?

Hey BHW!

So I noticed something strange lately. Whenever I turn on ads, my organic reach for that days post drops significantly…BUT on the days I don't turn on my ads my organic reach just shoots right back up (Imagine below)

Please keep in mind that the stats disparity will vary with follower count – I have roughly 15k followers so to see on the days I turn on ads my reach goes to 2k from almost 10k is strange.

Anyone else experiencing this?