Being terrified of death as a teen

(Please excuse my english, I'm not a native speaker!)

I'm a 16yo girl and ive been having constant panic attacks over this, every night basically. I know that i'm young and i probably shouldn't be thinking about this now but my brain just can't help it. I'm on summer break still (i get back to school next monday) and of those 3 months on break i had crazy panic attacks at least once a week, becoming more frequent now.

I always had these sometimes randomly, even as a kid. I remember crying to my mom as a 7yo. And you know, i think everyone sometimes becomes a little too self-aware, and i think thats normal, its human. But its one thing thinking about it from time to time, and its another thinking about it everyday.

I cant even say it. Just writing in the title of this post makes me cry and my breath heavy. Im so scared of it to the point I cant even watch movies or play games were characters pass away, which i obviously always could, but now it haunts me.

I think one of the reasons is that I could never imagine myself living past 18yo. I dont know why tho, but its been like this since I was a kid. Im not saying this like I wanted to off myself at that age, I just couldnt see a future for myself. And now I'm almost 18. Sure, 2 more years to go, but time flies fast, and i guess im still stuck to that thought. Going to college, leaving home, and building a life alone, are all things that will happen soon. Im growing up too fast, and Im so scared knowing that soon might be the end. Heck, anytime can be the end. But I dont want anything to end.

Im tired of this constant panic I have. I'm sure everyone has gone through this but having these every night when I know I'm young is like an endless nightmare. And I can't even bring myself to vent with anyone about this. Sometimes, when it gets too bad, I'll just go to my mom's room and sleep with her. How do i make these panic attacks less frequent? How can I simply stop thinking about it?