I took this combo years ago except I was on Xanax not Klonopin....

Klonopin is a depressant so it can and will cause you too feel spacey or tired. The Lithium can cause mental fuzziness. Have you been on 1200mg for a while or was this recently increased? When was your last blood work? were you in therapeutic range?

Can you cut back your klonipin? Or just not take the prn doses as often?

"Usually" your body will adjust given enough time. But only you can decide how long your willing to give it.

I finally wasn't willing to tolerate the lithium and cognitive issues it caused and I stopped it.