When I was exhausted a few years ago, working as a nurse and charity worker, I tried a vegan diet, cut out all wheat, coffee, tea, alcohol, processed food. I cooked from scratch, drank fruit and herb teas, at nuts, veg, fruit and a small amount of Olive Oil daily. I too had always been slim but drank a lot of coffee, ate haphazardly and not always the best foods. After a year I had lost 3 stone, was full of energy, slept like a baby and was awake early every morning. Not an easy diet to fit into a busy social life...but I managed. Try it, its cheap, easy and you will feel the benefits.