How to stop thinking negatively at night?

I’m having real trouble getting to sleep recently. Which is unusual because quetiapine usually knocks me out and has been great for my insomnia. But recently I just haven’t been able to stop thinking about the past. All the people who hate me, who have abandoned me, imagining scenarios of saying things that were left unsaid. It’s like it’s running on automatic and I can’t stop it. I’m so tired but I just can’t shut off my brain?