Does Oxycodone Induce Sudden And Extreme Lightheadedness?

I'm very concerned that I might have taken too much Oxycodone (Two 15mg) and am too afraid to fall asleep in fear of slipping into a coma. My symptoms include: sudden and extreme moments of euphoria/lightheadedness. I do feel very tired but like I said am very afraid of slipping into a coma before I actually fall asleep.