I am sorry to read that you are dealing with obsessive thoughts of death and dying.
I was pleased to read that you are going to seek out professional help from a therapist or Psychiatrist who specializes in Obsessive thoughts disorder. It sounds like the pain and suffering you are having from these obsessive thoughts are difficult for you to explain.
This is not an uncommon condition and is very treatable. Have you seen a physician re this issue at all as often medicaiton helps in controlling the obessive thoughts? For some individuals a mood stabilizer helps to stop the cycle of obsessive thoughts. Please do talk with a physician/psychiatrist re this option.
I hope you stick with us as we are here to help.
I hope that you are able to talk with your family, parents, grandparents, sibling or someone who is living with you. It is always good to be able to share a fear such as yours as talking about it helps you to feel better.
Please do talk seriously with Mom about getting into therapy as I feel this will be a great help for you. You should not have to feel sad and worried all the time at your age. Life should be good for you so do talk with Mom.
Also you may want to share with Mom that telling you about the whimpering makes you feel anxious about your fears of dying.
You are not dying dear Alex, you have anxiety IMHO.
Hugs to you and plese know we care.