The stones you passed come in many shapes and sizes. There is chaff that is often like sand and the wrinkly ones you describe were like stones, probably an older one since it was dark. The split pea ones were little stones from the smaller ducts in your liver. It is good you are going to flush in a couple of weeks. There are lots more where they came from. Try to eat healthy oils everyday like olive, coconut and flax. Eat lots of fruit and veggies. Avoid processed foods and hydroganated fats. And the headache is probably from toxins released. Drink lots of water and juices to rehydrate yourself. If the heartburn persists, you might want to flush sooner than two weeks.