When a person can't distinguish reality from fantasy what disorder is that?

MAGAvision

Sounds like the first Tuesday of every second month to me.

Could be any disorder of the content of thought, like schizophrenia, paranoid disorders, delusional disorders like Cotard's (people think their bodies are rotting) or erotomanic where they think that someone is madly in love and obsessed with them while it's clearly not true. There are many.

Schizophrenia or Bipolar disorder.

Youre most likely referring to schizophrenia; there are, however, many disorders that cause this.

Schitzophrenia or pyschosis

It could be pretty much any delusion.