Low energy levels can be a result of low blood sugar. Ensure you food intake is adequate. Increase meal frequency and ensure you are consuming a good source of protein and omega 3 fat with each meal. Increase your vegetable intake with each meal.

Ensure you are getting 6-8 hours of good quality sleep each night.

Ensure you are moving around at regular intervals throughout the day and not sedentary for long periods.
Reduce or eliminate your caffeine intake. Over time, high levels of caffeine can make you dependant on caffeine for energy and increase your fatigue in the long term.