The pituitary gland is tiny (10 mm like a kidney bean). However, it is nicknamed the MASTER GLAND as everything is directed from the pituitary. I have the same conditions. I have been taking Levothyroxine for over 20 years. This is specialised. Hence, why your GP has no idea or understanding. Do what you can when you can, whatever task you do: washing up, out for lunch or changing the bed….. they all have a consequence. You need to work out how tired each activity makes you and work with it. Do not fight against it. I can’t/ don’t plan because I don’t know how well I will be. I now have a wheelchair for hospital trips. I spend at least 15 minutes a day doing something I enjoy (watching the flowers in the garden, watching tv, talk to a friend. You are not alone, allow yourself time to “grieve your old life”. It is normal to think back to what you used to be able to do. Your ability has changed so, be kind to yourself as you would someone else. 🥰