Fear of death of my loved ones

When I feel my feelings, the very essence of my sadness lies in the fact that someday, I’m going to lose the people and pets I love the most.
I watch my parents, my dear aunts, and my so beloved cats get really old and can’t help but feel desperate.
I then do everything to keep them with me, I stick to them, kiss them, don’t go on holiday, buy them groceries, electricity, presents because I’m fearing of regretting anything later.
But truly this doesn’t help me feel better because in the meantime, I need to think of something else.
This is also one of the reasons I’m having a hard time finding companionship: I won’t be as much present with my parents.
Please, help me put things in perspective. I know that we are bodies with limited amount of time on earth, but that doesn’t seem to help.
Here’s one of my unintentional models:
C: loved ones are gonna die
T: I’ll miss them so much, it’s going to hurt so much that I don’t think life will be worth it. They are my whole world.
F: deep sadness
A: I wake up during the night, I feel my stomach hurting. I cry a lot when nobody sees. I am sticky with them. I don’t make plans for my life. I plan things for people so that they’ll enjoy their life and feel guilty if I plan something to myself because I might regret not having done it with my parents and not given them the opportunity to live that experience.
R: I alway have sad thoughts that I can’t get rid of