Don't assume that because you are a young spiney that the rules don't apply to you. I don't mean to sound harsh but like Lee, I have been at this for decades and have had numerous open, invassive surgeries under my belt. I have made all of the mistakes when I was younger and found out that the rules DO apply to the young as well as the older.
Lee is correct about the post op meds. Surgeons are notorious about undermedicating the patients post op. I was your age when I had my first spinal surgery.............bi-level disc/lam in the cervical region. I was discharged with minimal meds for one week......to take care of me until I saw the surgeon for my first check up. When I told him I was experiencing considerable pain, he looked at me aghast and said, "what's wrong with you? I fixed you." Such stupidity and arrogance. This was back before the internet and good peer support and info. I cowered and accepted his decision that all I needed was a muscle relaxer and tylenol x-tra strength. It took me forever to recover as I got little rest for months due to untreated pain. If you have a pain doc, get in to see him asap after the surgery for a good check up and review of your medications. Hugz.