Mr.Squishy said:
Reading your post was like a timewarp for me, it looked
exactly like something I could/would have written 7 years ago (I'm 26). It turned out that my parents hadn't prepared me for being an adult, and I had developed a panic/anxiety disorder due to that and other (worse) factors. I would have panic attacks over being in public social situations, but the number one anxiety that haunted me and wouldn't let me leave the house was confronting the reality that one day I would be gone and everything would be black.
I won't lie and say there's an easy answer. Seeing a therapist didn't help (he talked of reincarnation and kind of shrugged off that aspect of my problems, like he didn't want to be reminded of his own mortality). I eventually found a better professional who prescribed me anti-anxiety medication and they saved my life. I've since left the house, got married, had a child, and built things in my life that I can care for and nurture.
I know that the whole thing seems irrational, but that's what makes it a disorder. You probably had a dog or a goldfish die when you were younger, and accepted death. Maybe you've been to a relative's funeral, and helped yourself in accepting death. But sometimes our perspective can change and we look at things like death in a different light.
If panic attacks are preventing you from living a quality life, please seek help for them. The worst thing that can happen is having a fear of death that prevents you from actually living a life while you're here. You don't want to be on your deathbed saying "well at least I've put a ton of thought into this, and sufficiently worried about it!". Try to consider this re-evaluation of your mortality as an opportunity to do more things in life that bring you joy and make a life well lived. A ton of people don't think for 1 nanosecond about this unless they're in mortal danger, so you have an opportunity to make changes at this point to make the life you have better.
For me, it was donating to charity, doing some volunteering here and there, pursuing my music and writing with much more effort, and having/loving my wife and daughter and building a family. I'm driven now by a desire to do things for others so great that hopefully people won't have to work and stretch to say positive things about me when I'm gone. Essentially, giving to the world can be much more rewarding than taking or receiving from it, but if panic and anxiety is preventing you from even basic living, you'll be so glad you got rid of those first.
A lot longer than I expected, but you reminded me of a point in my life where all I did was ponder mortality to the point where I was being killed by the concept. I hope that you can use this as an opportunity to see what kind of life you want while you're here, and that you don't suffer with panic for long, because it's no fun. Take care, and feel free to PM me if you want to talk about anything at all.