It is normal to have detox reactions at the beginning. That is why authors suggest to start very slowly (ex: drops, teaspoon, etc...). After 3 to 4 days these symptoms should fade away. You should avoid these symptoms if you start real slowly.
Again according to authors the first morning urine is the best (between 4-6am) because there are more hormones, enzymes etc... after a good night rest. The best one during the day is approx 1 hour after meal.