You only used 2.5mg of oxy for three days? You shouldnt have disturbed your progress at all. The biggest part of getting off drugs is maintaining the mentality of wanting to quit, there will be slip ups, but if you get hung up on them you'll end up feeling like you failed and going right back to your DOC.
Just keep focusing on getting clean, you had a small slip up, it happens. Just get back on track and keep going. Good luck to you and congrats on wanting to get cleN