Red, Hope you get well soon. In case this is helpful where the cause of energy loss remains an unknown, consider looking around your environment for changes, ie mold/mildew, exposed chemicals. This may sound too simple, much to my autologous approach to health, but during this interim time try to get enough fresh air, some sun, eat natural/organic, and exercise. The bright side to a short term illness is that if you take on an additional healthy habit in response, that lasts a lifetime.