You sound very clear on why you need to make this change. Mixed feelings...bittersweet...mean you've been thoughtful and are not making this change in a rash reaction to a single incident.

I'm glad there are memories to cherish, and even more impressed that you're making this change in order to take care of yourself. Preserving your sanity is more important than any single job.

You sound like you've learned a lot and are leaving at the PERFECT TIME.

On to better pastures!!