Is it normal that sometimes i fear death a lot and sometimes i don't?

I think those are normal feelings to have about death. I don't have any advice, but I can share how I've felt about it in the past.

When I was twelve years old, I watched a movie called Shaka Zulu (1987) about the entire life of a Zulu leader. It disturbed me to see Shaka getting older and having to dye his greying hair to maintain youth and respect from his people. He struggled for so long, only to be destroyed by colonialism. I also watched Empire of the Sun and Platoon that year. I read Watership Down, Johnathan Livingston Seagull, and Animal Farm, then watched the movie versions.

Death didn't frighten me as much then, but the though of being an insignificant anecdote in the saga of human history consumed me for years.

everyone dies so dont waste too much time worrying about it

It is because of your moods. When you are manic you do not fear death and could just throw yourself into the fire while cheering and laughing like a witch sentenced to death by an inquisitor, or just throw yourself into a deadly fight, but when you are depressed, in other words sad, you get all whiny and stuff. When you are on lithium you just do not care either way.
It's just a joke, but yeah, it is mostly about the mood you are in when you think about it. Plenty of soldiers go fight a war and face their enemies risking to get killed every couple of minutes or so and why do you think death does not worry them that much? It is because they are being manic. They are in a murderous/suicidal rampage. They can't possibly go through all that with a "clear" mind. Religious people do not worry that much about ding because they believe in the afterlife and think they are merely leaving their bodies to go somewhere else. Unless they sinned a lot and believe they are going to burn in hell. That is when the priest steps in and forgives them for all their sins, so they stop being afraid of going to hell. The great unknown is way more scary than any delusion about a pretentious idillic afterlife. It also depends on how you imagine it would be, to die. Whether you are leaving unfinished businesses behind, and worry about all the people you are going to leave behind. If you know they are going to be fine and just do not need you no more, you can drop out without much fuss on your head, but if it is not like that, death becomes more unwelcome. So yeah, it is pretty much about what you think and how you are feeling while you are meditating on the subject. You think something then feel something according to what you have been thinking then you think something else according to what you have been feeling and so forth.
Kind of a chained reaction. Some thoughts push you towards anguish other ones towards, well other emotional outcomes. I just do not think about it, I think I am immortal. Just kidding. It is just that I have no control over these emotional and cognitive processes. Or maybe I do. Anyway.. Death will seek destruction.

Sometimes im scared othertimes i nearly laugh at it...