Hi Jayne
I am a 45 year old person who is going through much of the same thing you are. Here is my advice.
STOP SEARCHING FOR A DIAGNOSIS!!!!
The truth is, it doesn't matter if you are trans or not. You do not get to choose what you are, but you DO get to choose how you live your life.
It took me a long time to accept my dysphoria, and come to peace with it. I finally accepted that there is a large part of me that is, and will always be female, but I have chosen to still live outwardly as a man.
Ask yourself this. Is it within you ability to accept your dysphoria, but still choose to live as a man? For some people this isn't possible and those people choose to transition. But for people like me, this is an option. I find ways to express my femininity, either privately, or in ways that fit well into the life I have chosen (for example, my on-line presence is almost exclusively female).
So, they question you should be asking yourself it NOT "Am I transgendered?".
I think the question you should be asking yourself, is "Can I live my life without transitioning right now?".
If the answer is "no", then this suggests a course of action (HRT, etc.).
If the answer is "yes", then I suggest living your life and finding a way to accept the feminine parts of your personality.
Best of Luck,
Janet