My ex and I broke up about a month ago. I broke up with him because he was clingy, inconsiderate, selfish, annoying, wasted my time and other things. And now that we've broken up it seems like he still is trying to do the same things. He still insists on us being friends even though my entire point of breaking up with him was to be rid of him. He refuses to understand exactly what no mean and he's even followed me all day around campus waiting for me after class trying to talk to me; with no consideration of if I even want to speak to him or if I had something to do. He's even gotten violent with me if you times pulling my hair, pushing me, and lightly grabbing me by the throat. I'm going to get a no contact order against him, but I don't think that will be enough. What exactly should I do to keep him from going too far?