Crazy or Creative?

It sounds to me like you started to do this when you were young and it just became a part of you. Like a habit. Have you thought about possible seeing a psychologist. They may be able to help you figure out what caused this to happen to you in the first place. They are incredibly good at what you do and you may be surprised. It's also a great release. Someone that you can talk to about anything you want who is able to listen openly and give great advice as well.

Your behavior is quite easy to understand. You're seeking attention. Most of us do this kind of thing when we're young. We make stuff up because none of us feel as if we're interesting enough just being us. This is not unusual. The unusual thing is that you've let it extend into your adult life and you're now dependent on it. Seek help, seriously. This will end up making you a very unhappy person.

Have you ever considered talking to a counselor about your problem. Sometimes living in a fantasy world whether real or imagined sometimes means that your real self is too painful to be so you make up other characters to take the pain away of who you think you are in real life. This can get very complicated so I stronly suggest you seek out counseling so you can begin to understand why you do what you do.

I think a lot of people have imaginary playmates when they are young but after they start to school real playmates take the place of the imaginary ones.  If you are having imaginary FAMILIES at 20 then you should seriously think about seeing a psychiatrist.  You seem to be making up people to fill a void in your own life.  Don't you think people would find out?  Surely they are suspicious when they never meet your other "friends" that you talk so much about?  Get help now before it ruins the rest of your life.