So I finally confirmed with my ex that we no longer care about each other, and probably won't talk to each other again.
It's been needed for years, and I should be happy. Why am I not happy? Why do I feel completely apathetic, too much so to care about doing anything at all this weekend?
I guess it's my first "getting over her" time. How do I hurry this up? It's wasting my time.
>I should be happy
No, you really shouldn't. Whatever you actually feel is the correct response.
You hurry it up by getting on with your life, and not idealising her when thinking about her.
Do things to keep yourself busy. Pick up new hobbies, enjoy old hobbies, and most importantly TALK TO OTHER GIRLS. If you see a cute approachable girl, go for it. Even if she doesn't end up being the one, the act of talking to her will greatly help you move on.