Not memorizing the Win32 API or every function and facet of C/C++ is um..well...normal. There is far too much out there to memorize it all. That's why they make these really cool things called SDK's and help files. :D
I program using DirectX, Win32, and/or MFC nearly every day and still don't know what every interface and class is or does for that matter.
Besides have you seen the Win32 function for CreateWindow()? Are you seriously going to memorize all those parameters? I've got better things to do. Knowing how to find the answer is sometimes better than knowing the answer. In my small game programming endeavours research has gone a long way to solve problems that are oft not documented or simply not encountered. Each situation is unique and knowing how to find the answer is as good as gold.
Good luck with getting a job and I wish you the best. There is life after college.