[CW: Death, Dying, thoughts about suicide] How do you deal with being mortal?

Ever since I was a child I was afraid of getting older and dying. It has been in the back of my mind for most of my life.

I had phases were this fear was not really around and then phases where it is the only thing I can think of. Ever since Corona it has gotten worse and worse. It just struck me one day while playing video games with my friends. Suddenly I was like "I WILL die one day. I will not be anymore ... forever. I won't even know that I am not anymore." and I broke down pretty much immediately.

What followed was a phase of everlasting fear and anxiety. It was so bad that I just couldn't fall asleep unless I watched comedy until was physically not able to stay awake. Back then I thought it was a result of the isolation of Corona. Since then I moved back in with my mother (due to different reasons). Everything was fine for a while but now it is back.

I should be happy. I handed in my bachelor's thesis a while back, will soon move out again and have gotten a job in my dream career. I finished my therapy and while I am still not completely over my social anxiety but it is getting better and better. And yet the fear was never as bad. Last night I cowered into a ball under my desk and started crying.

It has gotten to a point were I thought about killing myself to end it. It is the same result either way. I won't remember anything anyway. Even the pain and grief friends and family would feel is only temporary. They too will be gone with everything that made them up one day.

I have no intentions of going through with it but it frightens me that I even think like this.

I don't know were this is coming from. Maybe from the feeling that I am wasting my life, that I am a failure and too far behind peers, that I am too old to have so little but I also know that it's not like I could have done a lot better. Due to circumstances outside of my own control I am were I am right now but I am doing my best to get better. It's just that it takes a lot of time and I fear that it takes too much time. I also lost a good friend recently so this probably plays into it as well.

Is there anyway of changing my way of thinking about death? I know I can't change the fact that I will die but how can I accept it without falling into existential nihilism like I currently am?

Edit: I also already called my therapist but since it's the weekend they won't answer before Monday.