When I deal with my hallucination and/or entity; I often use a stim toy to ground myself. The repetitive nature of the toy allows me feel a sort of control over something. As for the dissociating, honestly I just ride those out. I often "wake up" and realize I've self-harmed but the thing is, when I fight it I get closer and closer to a full melt down and will likely self-harm anyway. When I get like this, I play music all of the time, keep my hands focused on stimming and keep distracted by activities that have been known to relieve my anxiety (for me it's playing my keyboard piano).

Just gotta take it day by day. Hour by hour and minute by minute. Hell, get down to seconds if you have to. All you have to do is stay alive. I shouldn't say "all you have to do" because it can seem like an impossible task, but whatever you have to do to achieve it, please do it. I'm sorry you're in so much pain, but screw "signs", screw that mental health worker and screw that damn hospital for turning you away. Screw all of it. You matter here. Always.