I think i have a mental illness?

I hear people talking, nobody is around me, they talk about scary things like monsters and Ghost and killers. I see things that arn't really there, this has all started within the past month or so, Ive aslo become extremly disorganized and I've started to distance myself from my friends. I've started not to care how I look anymore. Im afraid of alot of things. I have extreme mood swings, can you help me? perferably is you know alot about this sorta stuff, thank you so much