Legally, many places may mess with you doing any form of euthanasia, “natural” or not. But literally, you are your own human agent. You can choose your best life, and you can choose your best death. It’s all about your will and agency to do it. Not many are so privileged to be able to die as they so choose. But you can use your mind to help you. Don’t worry of some naturally suicidal method you employ; but think of a properly true and natural method nature employs for you.
If I was you, then I’d just focus on the fact that to die is just as much as to live. Without death, life would not be such a special and rare gift. Just as you did not choose to be born and made alive you can also accept that you should not choose to die. Death should come as life did. Unknown and natural by it’s nature. Any death is natural, just as any life is natural.