Hello,
I also have experienced similar symptoms and history. I was diagnosed a couple years ago at age 48 after many confusing tests and doctors. While very active, I have had to change my exercise to mainly indoor and from cardio to weight training as not only I was getting out of breath fast but the cold weather was impacting my fingers and feet too much. I was treated with rituximab and it really helped for a year and a half. I will have another course early fall hopefully so I can be ready for the next cold temperatures.
Good luck with your CAD!