Get off the "Yaz" immediately and contact your physician. The problem may or may not be due to the Yaz. The Yaz commercials are pretty slick. The one with the smiling actress who pretends to be a physician and says "I didn't go to medical school for nothing" wants me to find the person at the ad agency who created the commercial and ask for a duel at ten paces. They don't show the people who have side effects that cause them to end up in persistant vegatative status. Water alone doesn't rehydrate. You need electrolytes. And you need a consult with the physician who prescribed the Yaz.
I have eaten bananas which help bulk up stool. Also, stay on fluids like soups and water, some gatorade or pedia-lyte for the minerals. This usually works after a few days or less. If you continue to eat heavy or solid meals, the stool will go through your system too fast. Wait until you feel better...
good luck...ps..some acidophilus for any bacteria in intestinal tract helps. too
Colloidal Silver from the health food store may help with diarrhea.
Don't drink juices because the excess sugar could make the diarrhea worse. Oral rehydration salts are what you need.
Acupuncture-wise, there are special points to stop diarrhea in the abdomen. Try pressing two inches sideways from the belly button. This works better with acupuncture needles than with pressure alone, though.
Better watch out for signs of dehydration.