Do I have schizophrenia?

According to what you're writing here, you don't. What you're experiencing are negative symptoms (dulled affect, depression, etc.), not positive symptoms (delusions, hallucinations, etc.) which distinguish schizophrenia from other illnesses. However, nobody here can tell you for sure. If you want an expert opinion, go see your GP or a psychiatrist.

I'd say you do have something you need to deal with so it doesn't develop into anything more severe.

Jam it back in, in the dark.

It does sound like anxiety, from a definitional point of view. But your fear of the anxiety itself makes it even worse. Here's one important thing to remember: Anxiety cannot hurt you physically. You won't faint or anything, since your heart rate increases. Anxiety can be a normal reaction, and there's nothing wrong with it. So when you next start panicking, remind yourself of that.

You are very concerned about it, though, so again, you might consider going to see a doctor.

There's nowhere I can't reach.