What possible reasons could be blamed for my wife's continued loss & lack of energy?

Needs work up!: She should be seen by her pcp as soon as possible! she needs a complete physical, ; a much more detailed history.

Anemia, hypothyroid: Common causes of such symptoms in a previously healthy individual are the development of an under active thyroid or the development of anemia, either due to occult blood loss or heavy menses. Simple blood tests will determine if these conditions exist.

LACK OF ENERGY: There are many causes of loss or lack of energy. She needs complete checkup physically, laboratory, and mental problems like depression, chronic fatigue sycdrome or hormonal like menopause.

Many possibilities: There are many possible causes of your symptoms: many type of infections (bacterial, viral, fungal, parasitic), anemia, nutrient deficiencies, food allergies, toxic exposures, thyroid ; other hormonal problems, sleep disorders, heart disease, stress, depression, side effects of medicines etc. See a good doctor, preferably one with a holistic perspective, for a thorough evaluation: http://bit.Ly/19pettq.