heyo!
First off i like 2 state that this is a common problem. I suffered of nite anxiety during 3 stages thro my life... i also have a younger 12 yr. old brother who is dealing w/it right now. Nite anxiety can be caused for many different reasons.
I personally will not share my reasons or brother's mainly because of how this is not private. But please feel free 2 PM me if u would like 2 relate...
On-to what u r going thro... Nite anxiety is very common because it takes all of our fears & problems that we dun have time 2 concentrate on or fix during the day & starts acting them out @ nite. Causing us 2 go into nite terrors & such. & believe me i know how it feels & it is in no way pleasent.
Sadly, 2 get rid of them a lot of the times u have 2 be placed on anti depressents 2 help calm u down. Personally i feel its the best way, but depending on how u feel u may want 2 try other things.
Another good way is 2 try talking 2 someone about how u feel about all this worry of death. If u could get it out sometime during the day 2 someone ur brain may not overreact so much throughout the nite.
I really would like 2 help u w/this because i know how u feel. PM me if u have any questions or just 2 talk more about it...