urology institute- a com site says:
"Q. If I get a kidney stone, what are my chances of passing it?
Dr. Green: The size, configuration, and location affect the spontaneous passage of stones. However, stones less than 4 mm in diameter located in the lower ureter have a 90% change of passing. In contrast, stones greater than 6 mm in diameter have only a 20% chance of passing spontaneously."
So, I don't think you could do it without getting medical intervention to make it smaller first, since yours is 16 mm.
From medicine net's website:
"A 4 mm stone has an 80% chance of passage while a 5 mm stone has a 20% chance. Stones larger than 9 mm-10 mm rarely pass without specific treatment."
So, I hope you get to the doctor's and get the help you need!