Do i have schizophrenia?

I don't know when this has started happening, but i have a voice inside my head that i think is a different version of me.
It's my own voice in my head that i talk to through my own mind. This other version of me can be very mean and rude. It insults me, insults my religion, tells me things about my girlfriend that leads to an argument, and i'm not sure what else.

Most of the time it'll tell me not to talk to my girlfriend and just play games. I get sort of angry and my mood changes. I end up ignoring my girlfriend sometimes for no reason. After i make her feel bad, my mood changes back and i apologize to her and comfort her immediately. I try and fight it, but sometimes i give in for some reason. I don t really know what this is... does anyone know?