What's wrong with me?

Maybe you're not getting enough of some vitamin but since you said you take vitamins, I don't know. Maybe you're getting too much of some vitamin. It's definitely good you made a doctor's appointment, don't leave any of your symptoms out when you're telling them what's wrong. Maybe ask about having your thyroid checked. I was feeling like crap all the time for no reason and I couldn't figure it out either. My doctor checked my thyroid and found that it was overactive. I'm told thyroid problems can do all sorts of weird stuff to your body. Good luck though!