I Have Been Water Fasting For 5 Days. The Last

I have been water fasting for 5 days. The last couple of days I have felt very nauseaus and sometimes gagged. I ve also been stomach pain, cramps, even light diarrea. Today I've been throwing up small amounts of what tastes like pure acid. My latest vomit was a full cup of brown acid. What do you think is going on? Are these normal side effects of fasting? I'm just gonna Google it. Thanks anyway.