Your low energy today is your body telling you to make a change to your exercise or diet.
If you are feeling sluggish today it could be your body telling you, you need to make a change. One small change to your exercise regime or your eating habits, could be all that's needed to see your energy increase. If you are not sure what you need to do, go to someone with experience, maybe an expert, and get some advice about how to up your healthy living.