I was having similar issues, with being sleepy and having absolutely no energy at all. I would literally trade just about anything for sleep! To the point where if left alone, even though there were other things i wanted to do, i needed so much sleep i'd only wake up for food! Checked my blood work & everything was fine- I was eventually diagnosed with a sleep disorder (hypersomnia). Everyone kept telling me "oh you just need to be exercising!" It was sooooo frustrating! I was like "I can't exercise if I can't stay awake to do so people!!" I'm now on a stimulant (vyvanse) usually used for ADD/ADHD and its the only thing that allows me to function on a "normal" or socially acceptable amount of sleep.

I hope you get everything figured out!