I suggest you don't listen to natway, he keeps saying people are feeling crap because they don't ingest enough calories.
Thousands and thousands of people have fasted on vegetable juices only, myself included and felt absolutly great once their bodies were in a cleansed state.
What you're experiencing is die off. If you're eating only low-carb vegetables, the detox can be quite intense and I wouldn't recommend that because we do need some calories at some point. You do need some carbs, but go for the low-glycemic ones and beneficial for the detox like raw beets, carrots and jerusalem artichokes. Also, not getting fats at all is not recommended. If you don't have any in your diet, you're gonna feel crap. Why? Mainly because it is needed to produce bile, and bile is the carrier for the toxins the liver filters. So unless you're doing several coffee enemas a day or drinking beet juice, the bile is stagnant and the toxins from die off accumulate in the liver. I just read that you're taking turmeric, which is a cholagogue, but you're probably not taking enough of it for getting that effect.
If you feel crap, consider a coffee enema, or even plain water enema. Don't allow yourself to be constipated. During detox, 2 good bowel movements a day should be a minimum.