To fear death and/or uncertainty is part of the human condition. You're not alone with these feelings, especially not with a pandemic going on in the world right now.
Mindfulness is a good start. Also, there are "the five recollections" that may seem a bit cynical at first, but serves the purpose of reminding us to get used to the fact that everythings ends. They are:
- Losing loved ones
The last of these five reminders tells us that the only thing we really can own is the consequences of our actions. This can sometimes help in reconciling fear of death, as it may shift our attention to how to live a healthy life (The buddhist idea of a healthy life is perhaps different to a laymans idea of a healthy life).
That's kind of a personal question, isn't it. :-)
In my experience, when someone who you love dies, then you understand death to be ever-present. When you think of death then you think, "I (we) have already died" and "I know/experience what death is" and so on.
Even that is probably something which Buddhism defines as a "conceit", i.e. a kind of fleeting or residual sense of "self" -- How are 'conceit' and 'identity-view' not the same?
The whole doctrine of "self-view" is difficult to explain, or easy to explain but difficult to understand. Briefly, I think it's that having a sense of self (e.g. "I exist") is a cause of suffering (e.g. "woe is me, I will die") -- so a part of Buddhist doctrine, the beginning of enlightenment, is the abandoning of "self-view".
Another angle is to understand that what you sense and perceive is always changing, is impermanent, appears and vanishes. So to the extent that you identify with that (e.g. "I am what I see" or "I am the owner of these sights"), that is always changing or flickering, appearing and disappearing, all the time. So you might see "thought moments" as arising and ceasing continually, even several times per second. And I think that that kind of discontinuity is related to the Buddhist understanding of death -- see e.g. this answer, "True death only occurs either at every moment or at the experience of nibbana."
Then there's also e.g. this recent topic -- Can I plan for future while doing meditation on death? -- which seems to is based on this sutta.
I'm not sure if this will help but that sutta reminds me of this Zen story (i.e. from another tradition of Buddhism):
Three Days More
Suiwo, the disciple of Hakuin, was a good teacher. During one summer seclusion period, a pupil came to him from a southern island of Japan.
Suiwo gave him the problem: "Hear the sound of one hand."
The pupil remained three years but could not pass this test. One night he came in tears to Suiwo. "I must return south in shame and embarrassment," he said, "for I cannot solve my problem."
"Wait one week more and meditate constantly," advised Suiwo. Still no enlightenment came to the pupil. "Try for another week," said Suiwo. The pupil obeyed, but in vain.
"Still another week." Yet this was of no avail. In despair the student begged to be released, but Suiwo requested another meditation of five days. They were without result. Then he said: "Meditate for three days longer, then if you fail to attain enlightenment, you had better kill yourself."
On the second day the pupil was enlightened.
Several of these "101 Zen Stories" are about death -- I like the one about "The True Path" for example.
Another part of the doctrine is, what are you going to do instead of being attached and fearful? And a Buddhist answer to that might be that you try to do the best you can in the circumstances, which should lead to a lack of regret (an absence of remorse), and so on.
Another part of the doctrine is caring for others and trying to avoid seeing yourself as special. I don't know but I think that Tibetan Buddhism might identify self-cherishing attitude as a fundamental problem or source of misery. Although conventionally I'd identify the Three poisons as being the "unwholesome roots".
Since one who has entered the stream has nothing to fear with death, losses such fears, it's surely the best to give much effort to gain it as soon as possible, good householder. Maybe of good support: Into the Stream: A Study Guide on the First Stage of Awakening. A streamenter is directed toward highest liberation and his max seven birthes to come are in good families or in the Deva realms. Don't forget: death is just a point on a wheel and usually no end, but each new starts quality depends on many things & could be in many spheres, insec.
It's natural that one who loves the life will dread dying.
There is nothing you can do to have one without the other.
What we cherish that we don't want to lose.
Therefore these anxieties are embedded in the notion that existence is categorically good.
To change it one has to reevaluate both ends.
Here are main lines of categorical reasoning that could be considered;
are phenomena stable, permanent or impermanent and unstable?
phenomena are afaik impermanent and to that extent unstable.
is that which is impermanent & unstable reliable or unreliable?
That which is impermanent & unstable is to that extent unreliable.
That which impermanent & unreliable, is it controllable?
No, that which is impermanent & unreliable is to that extent uncontrollable.
Is that which is unreliable, uncontrollable, unstable & impermanent, is it subject to change?
Yes, that which is unreliable, uncontrollable, unstable & impermanent is subject to change.
Does the change depend on conditions, is change conditioned?
Yes, change occurs when conditions change, to that extent change is conditioned.
Is that which changes conditioned or unconditioned?
That which changes is conditioned [changes when conditions so dictate].
Being conditioned, unreliable, uncontrollable, impermanent and a subject to change. Are these characteristics a basis for happiness or stress?
To the extent that phenomena are conditioned, unreliable, uncontrollable, are impermanent and are subject to change, these phenomena even if pleasant are subject to change and are to that extent stressful.
Now is it appropriate to regard that which is conditioned,uncontrollable, unreliable, changing and stressful as a self or belonging to a self?
It is inappropriate to regard that which is conditioned, uncontrollable, unreliable, changing and to that extent stressful as one's self or belonging to a self. There is here no basis for regarding these to be a self or belonging to a self.
This goes then for behavior, thoughts, feelings, perceptions and so on.