First of all, you shouldn't be afraid of anything you post here. Everyone has a demon here that we are not proud of, but the fact that any of us are here in the first places means that we are all willing and able to stand up to those demons, together, instead of facing them alone.
From what I read, you seem to have put up a disguise for everyone your entire life and that it has become something of a safety blanket for you. To harbour feelings of remorse, jealous, anger, pain deep inside yourself while presenting a positive exterior to everyone close to you. If I can say frankly, is that for your own benefit, or for other people? That you are afraid to show others the real you, or that you are afraid of what they would think of you?
In any case, it is not healthy to do that - you can see the results in your own writing and lifestyle of becoming a recluse and one that will only get worse as the years go on.
I can understand that you might be afraid of going outside except to the shops - I am much the same way half the time - but nothing ever changes in life if you keep hod of the things that make you feel safe in life. It can be a scary, daunting thought to cast away everything that you are comfortable with and that you know will never cause you hurt, but that is not living, I'm sorry to tell you. Life has always been hard, physically and emotionally, and if you do not experience those hardships in life, the you will never grow as a person. You will never change. You will always wake up in the morning and take a look around your residence and fall ever more into depression and despair. I had done that exact same thing.
One of your friends who you are going to see, you have not seen in roughly 35 years correct? Why would she expect you to be the same person as she knew all those years ago? It is a long time for anyone, and you might just be surprised at how much your friend has changed in all of that time, not only lifestyle, but way of thinking? Everyone says they are doing very well in the world, career-wise, family wise, friend-wise, et cetera, but why should you worry yourself about what anyone thinks of you or the choices that you have made? The are just as legitimate as the choices your friends have made for themselves. Sure, it might not be as glamorous as your friends, but they have no reason to judge your choices, much like you have no reason to judge them or that I have no reason to judge why so many people prefer watching SpongeBob Squarepants over Dora the Explorer.