I feel like I’m gonna die soon

I don’t know how to fully explain this feeling.I’m certain that I’m going to die soon. Actually I’ve been taking antidepressants on and off (SSRI) and I would take 5 mg for days then switch to ten, then not take it for some days really depending on my moods. Honestly, I got very paranoid I felt like taking them would change me completely and make me an idiot for the rest of my life. I also had some very troubling thoughts about burning myself it was almost as if I was obsessing over the idea of doing it . I wanted to burn myself to death so bad. I just stopped taking them abruptly. It’s been three months that I haven’t seen my psychiatrist and now I’m obssessing about my death.Btw I’m diagnosed with severe depression.I can’t stop thinking that I’m going to die soon, I’m not as depressed as I was before it just feels like I’m not living in reality idk it’s just a very weird feeling I feel like I’m dreaming and I’m always distracted I can’t concentrate on anything. This is so weird it’s scaring me. At times I feel like someone’s watching me or I can’t look at myself on the mirror because I feel like I’m looking at the devil.It’s very hard to explain, I feel like there is someone in me trying to hurt me, someone whispering to me that I should burn or die. And I get so overwhelmed by that voice that I find myself very close to doing what is being said to me then in a blink of an eye I feel like I’m back to reality and everything feels like it was a dream. Once I got guided to the rooftop and I was standing at the edge about to jump, it almost felt like I was mesmerized. Other times I burn myself pretty badly ( third degree burns) it makes me laugh hysterically.I feel ecstatic. My response to pain is very abnormal especially to being burned. Please give me some advice idk what the hell is happening