I know that when I first started a diet I was very sick, muscle aches, fever, horrible headaches, it was nasssty!! But I was likely going thru withdrawl from sugar/wheat, and I also experienced more trips to the washroom, due to more fibre. But that was just my experience..
I would definitely take some time off from exercise, and up those calories! I weigh 10-20 pounds less than you, and I eat between 1800 up to 2000 some days (altho I keep my fat around 30 grams/day). Take some time, don't exercise! And you'll feel better soon
-Aimee