Barbs4Hugh - OK, but I need plenty of information to give a decent answer. To stay with:
How many cups of coffee or tea do you drink a day?
Do get any exercise - walking, cycling, running, swimming etc?
What do you eat?
What occupies your thoughts and feelings most of the time?
Do you realise you are a mammal, and like other mammals, need regular exercise, decent natural food, rest and a mate?
To start with I would suggest a good multi vitamin and mineral capsule taken daily, Also take 3 capsules of 30mlg Q10 - these are a major re-invigorator.
Most foods people eat are without necessary B vitamins because they eat all white flour products, and also white rice. They lack enough vitamin E and C. So get a first class multi vitamin and mineral capsules.
Tony