Post 3-Day Water Fast

I went on a 3-Day Water Fast to cleanse my body and rid of toxins. My first two days went smoothly. My third day was horrid... I had the chills, nausea, and migraines all day. I had a very difficult time falling asleep at night. It felt as though I had the flu. However, I did feel great the next day. Throughout my fast I only drank water and coconut water to get nutrients. Now that I am off of my fast (it has been about four days), I can hardly keep anything I eat down... The past three nights, I eat, and I end up vomiting it up. It is impossible to keep down! And when I do keep it down, I don't have a bowel movement. Can someone please help me figure out what is wrong? Has my stomach shrunk? Or is my digestive system all out of wack? Thank you.