You have my sympathy. Doctors often try to treat the symptoms when they should be treating the cause, although signing you off work is removing one cause.
Low testosterone is interesting. Physical exercise should boost or at least maintain testosterone, I would have thought? Men are "designed" to fight and be very physical, e.g. to run for miles in pursuit of prey, and I strongly suspect that maintaining physicality through suitable exercise must therefore have important health benefits.
Being in good physical condition also means your body "knows" that it could fight if need be, so your panic attacks should disappear, since your brain will know that if it came to it, you could fight and defend yourself.
To get strong and fit, you don't have to sign up to a gym and start lifting weights. Just do 30 press-ups and 50 sit-ups every morning, and go for a gentle 10km jog once a week, or a 5 km jog twice a week. Cut out all sugar, almost all salt, and eat healthily.
Good luck
