What do I do with this?

Last week I was thinking of going down on my lithium, but didn't. Then this morning when I was taking my meds I noticed that there was a lithium pill still in my pill box. I normally take 3 pills, so last night I only took 2. This was not on purpose. And I had noticed this morning that I felt lighter, better in some way. Before I noticed the lithium. I didn't know what to attribute it to. 

Do I keep with the lower dose? Go back up? Go up to 750 for a couple of weeks and then go back down to 600? 

Part of me feels like I should call my psychiatrist- that I don't want to be doing this behind his back- especially after last session. But I don't want to bother him with a phone call. Or have him tell me not to do it either. 

I'm not looking to get off of the lithium. It really did get me out of the horrible, very long depression that I was in. But I have sometimes wondered if I could get by with less, given that I have the Zyprexa on board for a mood stabilizer. Especially given that I struggle with numbness, lack of initiation, etc. More isn't always better. 600mg is often enough to augment antidepressants. 

But I also know- from experience, that going down too fast on lithium can be very destabilizing. 

I think I will try 750mg for a while. And see what happens. 

Just when I thought I was done with messing with my meds for a while. Except for the klonopin- I am almost off of it.