Taking pain medication when you obviously need pain medication...even oxycontin...will not cause you to be addicted to pain medication.
I know 2-3 weeks is a long time to have to suffer...but you might want to get through the sleep study before you add on or change medication, as that might show something treatable (with meds) and all those meds would need to be adjusted and maybe changed to accommodate each other.
I do hope you've talked with the clinic where the sleep study is being done to ask some very basic questions, like:
1. What do I need to bring with me to be comfortable through this? (will they allow you to wear your own sleep garments, for example, and not that silly hospital robe thing?).
2. What do I need to do if I wake up in the middle of the night and need to use the bathroom? Who will help me? What will that entail?
3. Should I stop taking in liquids 2-3 hours before the study is done? (which will maybe help you not have to go through the bathroom routine)
4. Should I take my regular meds that day, at the usual times?
Good luck with that. I hope all this comes together soon with some concrete answers for you.
...I am not a doctor, nor health professional, and don't pretend to be one, here.....