The good news is that you already know how to program, even if you are intimidated by OOP. The other commenters are probably correct in suggesting that previous coursework from your class will give you the best sense for what you'll be tested on but, if you have 10 days to learn about OOP/C++, you could do worse than spending at least a little time reading some well-presented explanations of classes, inheritance, operator overloading, virtual functions, polymorphism, and the like, as a means to supplementing the language-agnostic programming concepts you already understand (through your adventures in PHP and JavaScript).
There is a ton of C++ info on the web (of varying quality, of course) but sometimes I think, when trying to learn something new, getting offline and looking at a physical book improves my focus.
I've read many C++ books over the years, but the one that finally made everything click, at least for me, when I was first learning C++, was "C++ How to Program" by Deitel and Deitel. The copy I have is 20 years old (yes, I'm old :) ) but I suspect the newer editions (http://www.amazon.com/C-How-Program-8th-Edition/dp/013266236...) have similar approachability.
Good luck to you and, as others have suggested, do not panic. Though it seems like a massive deal to you right now, rest assured your perspective will change down the road.