Hey all, does anyone have tips for staying more energized through out the day?

I eat well (pretty clean and not in a huge deficit or anything), exercise, get 6~8 hours of sleep a night (depending on whether or not I get waken up through out the night) and so on. I also drink minimum 2 liters of water per day. I only take caffeine on days I work out as part of my pre-workout.

Despite this I just constantly want to sleep and am lethargic. Does anyone have any ideas on having more energy throughout the day and therefore being more productive? I hate just sleeping the day away.

I just don't think I'm doing anything hugely wrong to warrant this level of energy consistently.