being only 19 I wouldn't expect to see a lot of stones unless you really really had a terrible high-junk diet for all of your life!
Go by your symptoms. If your symptoms are getting better, then you're stone free and need to work on dredging the liver of things OTHER than stones and increasing the liver's capacity for bile production. That means herbs and diet.
Usually four stone-free flushes in a row means you're clean. Wait at least 2 months before your next flush and do other things to clean your liver.