Wake up Exhausted

I really hate the term 'wake up exhausted' but it's been true for me the past few days. I don't know what it is, I'm getting 7-9 hours of sleep each night which is what's recommended. It's just frustrating that I never feel well-rested. Especially with all the stress of upcoming exams & final essays. My earliest class is at 9:15am and even that seems too early. The rest of the week is 10:15am and even then I still bum around getting ready in the morning like I've only been asleep for an hour.

Hoping I'll get out of this slump soon, though. I can't be sluggish when I write exams in December.