I really don’t think you have schizophrenia. What you may have is an episode of obsessional thinking. You apparently can’t let go of an idea that is distressing to you. Even when you tell yourself not to think about it, you are thinking about it. Your mind has become trapped in a loop of thinking about it, wishing you weren’t thinking, thinking about how not to think about it, which means you are thinking about it. No wonder you are upset!
You need help finding an exit ramp off the loop. The way out is to see a cognitive behavioral counselor who can give you some practical tools and some support to stop the loop. Really. A few sessions is likely to put an end to it.
I wish you well.