Great job in getting to day 10. Following are the answers to your questions.
1. Gas is produced from bad bacteria dying.
2. Each fast is different and drinking water only takes a wile to get out hunger mode. Also it is false hunger.
3. Sexual stimulation or any stimulation is not a good idea during a fast. Also sex has nothing to do with hunger gone.
4. Drink water per thirst. Your body will demand water when it needs it. Most people over drink in fear.
5. Soaps and shampoos are ok as long as they are not chemical ridden. Organic and natural soaps are fine.
6. Head rush is a sign of weakness and not feeding your body with micronutrients, which only come from plant based foods. Again, all fasts are different.