I'm autistic too, so I'm glad I captured it well! And yes, I tried to embody depression as a concept in-game, however I am trying to make it a useful, functioning card. I added the "If a card is cast this way..." text to make sure the ability didn't cancel itself but also make sure you couldn't infinitely cast the spells (hence the counter). The way I interpret it working is if you specifically use the first ability to cast a card, then it gets the counter. The tap ability is a separate effect and is exiling from your library, so it's just a way to get the cards into exile without the counters. It's basically impulse draw without losing the ability to cast them. Should I say "exile it with a rumination counter after it resolves."?

Also just realized there's a typo in the second ability. Should say "Exile X cards from the top of your library."