I am age 72 and no longer fear death. In my twenties and thirties I did panic much like you. I could not go to sleep and paced the house worrying about it even though I had a husband, children, job and a few close friends. I have been on meds too.
Life does not fly by, it's long and slow and living is hard. "Life is hard" my 92-yr-old neighbor said to me a few days ago. She lives alone, as do I, and cooks, does her laundry and except for brief illness mostly looks great.
By age 40 ( Life begins at 40 was true for me) I was too busy to think about death. I was consumed by the needs of others. Now that I am older it's mostly good and I don't mind the idea of being dead at all...it comes with being old. The fear is totally gone.
Life is a terrible storm with lightening bolts of joy. Wait for the bolts.
You'll be okay. (hug)