went to a dietician and she told me i wasn't getting enough protien or carbohydrates. or calories for that matter. I've modified my diet accordingly, eating 1800-2000 calories a day, basically doubling my protien intake and adding healthy carbohydrates and i'm feeling great. I just moved my weights up another notch at the gym.
It's been really interesting to watch how the change in diet affected my body. For a couple weeks, I gained weight like mad and craved sweets. Now I'm settled into the diet, and I'm not losing any weight but it's redistributing itself - I'm starting to see more muscle.