unfortunately i dont know much about hormones, especially DHEA. sorry!
but, looking at the drop from your morning cortisol to your noon cortisol. it does look like you would really benefit from a supplement that extends the life of cortisol. PABA or Licorice root are probably the best. if you often feel a little sluggish around noon, consider taking some Licorice or PABA in the morning. you seem to be the perfect case for those supplements.