Essays for School

So, in my first semester, in college i had a writing class. In this class my professor taught us MLA format, when writing essays. Now that I am in my second semester and have a new professor, he had basically told us to throw MLA out the window, and now I have no format. As long as it makes sense, its OK? What the heck!? It is like I wasted my time taking a class (I have to have for my degree) for nothing. To not even learn what I used.