Another question is whether this is “normal” for you. You’ve had two important losses in your young life — losses that taught you not to take life for granted and that you needed to depend on yourself. Those are not bad lessons to learn. It’s also not a bad thing to be analytic, especially in a family where people are hypochondriacal. You’ve learned to stop and think about whether symptoms are real. That is often the focus of Cognitive Behavior Therapy. You figured that technique out all by yourself.
I think we all make a daily decision about whether to see life’s events as mostly positive or negative. The difference is that most people just do it automatically and unconsciously. You are more aware of the choices you are making than most.
Are you normal? I can’t tell on the basis of a letter, of course. What I can tell you is that the range of “normal” is enormous. You have responded normally to life events. Whether you’ve taken it too far is something you’d need to talk to a counselor face to face to figure out. If that would give you peace of mind, I hope you will do so. A counselor can help you dig deeper and gain more insight into who you are and what you might want to work on to be all you can be.
I wish you well.