It's possible you could be having a die-off reaction, yes. Be kind and patient with your body as you heal. Drink plenty of water and get lots of rest. It will take about a month or more for your body to completely rid itself of toxins. I would recommend eating plenty of steamed organic vegetables and easy-to-digest soups and stews.
You might also want to invest in a Bowel Cleanse once your symptoms have stabilized a bit.