Is it normal to talk to someone who isn't there?

Ever since September in 2013 I've been talking to people who aren't there. I know they aren't there. I can't feel hear or see them. And the people I usually steal from books or shows. So far I have 7 people. Their names are Will, James, Sebastian, Ciel, Hikaru, Kouru, and Sasuke. (Most of them are from anime shows.) I act like they live in my head. I feel mentally ill. Plz tell me if I'm crazy.