Well, I did it. I told my ex of two weeks that I need space to get over him, and that I don't want to see him anytime soon. He said he was sorry. I told him if he wants to work things out between us then call me (and said that's if I even want to, that is, by then), but otherwise I need space and I'll call him if and when I can be just a friend to him. He said ok, and that he understands.
I told him this after he started discussing that he's getting me a birthday present soon. His response to why, was that he still considers me a "good friend" and so he wants to get me a gift. It's so hard telling him those things, because I want us to be together, and he knows it.