Can you call 999 when you have paranoid schizophrenia?

I have been diagnosed paranoid schizophrenia but I'm certain there's a serial killer watching me, hacking into my phone and computer, spying on me through cameras and who's eventually going to kill me. I've been thinking that maybe it's not my illness and it's actually real, I feel like I need to call 999 to be safe and make sure there's no one there. I'm really really freaked out, I can't stay still it's horrible.