Well, there are carbs. Eat carbs, serotonin jumps. But then you crash, which is why we crave carbs.
Turkey. High concentration of 5-HTP which does NOT make you drowsy like many believe. Your body synthesizes it into one of two things:
If it's near "bedtime" you will produce melatonin, which *does* help you fall asleep.
If it's in the daytime, you will produce...you got it...serotonin.
Eating healthy omega fats, such as that found in fish help support brain function. Part of brain function is producing serotonin.
Getting quality sleep and taking a nap will also help.