Your professor must not have liked you. I had a similar experience, though on my own and not for a class. Not my cup of tea. When I ran across Wittgenstein again, his biography attracted me more than anything. I decided to give him another shot but started with this book by Ray Monk, who was Wittgenstein’s friend, biographer, and also the author of the article I linked. Unlike most short introductions to philosophers, I found this one extremely valuable and still a good guide to the major thrusts of Wittgenstein’s work.