There is no reason to bump your own thread five minutes after posting. Give it some time for people to read, and respond. you WILL get an answer eventually.
Now, if you do not have any tolerance to opiates, 15mg is definitely a high enough dose to make you sick. When I started taking opiates that much would have me puking as well. Try taking 10mg next time, and see how that works.
It is best to start small and work your way up. You can always take more if it isn't enough, but can't un-do it once you have taken it.
Your friend doesn't get sick, because he has a higher tolerance to oxycodone than you.