I've been dieting and now find i don't have the energy for my usual exercise program. what should i do?

Change diet: A proper, sustainable diet should give you energy, not strip you of it. Consult a registered dietitian or physician for a proper diet for health and energy.

Balance: It is important not to try to lose too much weight too fast. Not enough food will cause low energy. Additionally, your body will panic, thinks it will be starved, and then start storing calories. Best to shoot for 1 pound per week which means cutting 500 calories a day. This will still provide the energy you need for daily activities. Keep a food log to assess daily intake.