i know your post is very old (5 years) and you may have found the solution to your problem by now. However, reading about your symptoms (which is exactly what i've been experiencing myself for many years before finding the solution) does not rule out the possibility that you are still out there looking for answers.
For all those people out there suffering from similar symptoms, i advise you to have your thyroid checked. Most, if not all of these symptoms can be caused by hypothyroidism. It can be tested through a quick and inexpensive blood test (TSH, Free T4 and T3). By doing this simple test you will have either found the cause of your "disability", or at least removed this option from your list. It is, in any event, much lest costly and invasive then CT scans and other complicated medical procedures.
A very high number of people suffer from hypothyroidism, and in most cases it goes undetected and untreated. Although not life threatening, it is very debilitating, as it affects the quality of one's life and (professional and personal) performance. Hypothyroidism can be treated by taking synthetic hormone replacements, and the right dosage can bring you back to your old self - energetic, sharp and enthusiastic! It definitely changed my life.View Thread