In my mind, I'm thinking, "Am I supposed to tell you that my body is tingling right now and I'm dizzy and I can't think clearly (and other very sensitive things)"??? It's hard to know what to say, so my answer is almost always, "I'm doing great"!
My MS doc often speaks about how in Western society, it is a societal norm to make small talk such as by asking one another "How are you today?" I feel that if you're talking with John and Jane Doe on the street, to say the norm "great" "fine" "ok" etc is fine because they are not part of your Village - your inner circle. They have zero business knowing your business. HOWEVER....When in your doctor's office, I feel you should be as blunt as possible. When your provider asks "How are you doing?" Tell him the absolute truth. "I feel like shit" "l feel like I've been hit by a truck" "if I scratch my head one more time I'm going to break through my skull" "things suck" "life sucks" "I'm depressed" "angry" "lonely" "scared" etc. Your provider is there to help you and if you are not as truthful as possible, he cannot be as helpful/useful as he could be.
I always reply, “I am fine thanks”.
I have developed a modified response to the question myself: nowadays I just say: "I'm vertical!"
I can't talk above a whisper and then it sounds funny. So I smile and mouth the words "I'm good"
I usually tell people "I'm alright". Or, pretty good.