Yeah I wouldn't burn too many brain cells on this right now. You'll learn to understand women over time. There is a reason there is a saying that 'Men are from Mars, women are from Venus'. Women do tend to be predictable though, even when emotional messes, even if you can't understand why at the time. It took me a long time to figure them out, and I just roll my eyes at the predictability now. Like, should your current girlfriend find out that a shirt in your closet was bought by an ex, you might as well just throw the shirt in the garbage, even if you have no attachment to the ex anymore, or how nice the shirt is. Just the way it is, no sense in fighting it.
But, if its one thing I have certainly learned is that while men mourn the loss of a relationship after it ends, a lot of women will do it while in one, all the while not saying a word about it (although you'll realize later there were hints of the demise taking place that you didn't pick up on). That's a big reason why you see how quickly they are able to flip the switch and move on to another guy so quickly. Plus, generally they hate to be alone and all they have to do is bat their eyes and get another boyfriend pretty easily. In all likelihood she lost interest in the relationship further back than you realize. Sucks, but that's just the way it is. You are definitely doing the right thing telling her you want some space, and I would just ignore her for awhile too. There is no sense in lowering your standards to keep her in your life after she just told you she doesn't want you to be a part of hers. And you don't have to be mean about it. Just be as matter-of-fact about it as possible. Actually, you moving on will probably drive her nuts. But either way, you don't want her back after this. That 'if it was meant to be, set her free and she'll come back' whatever crap, is horseshit. All its really saying is that you are a douche with low standards. Don't be a douche with low standards.
I gather you are a lot younger than I am, so I will pass on some advice I wish I could go back in time and tell myself: (1) Live for yourself first (and that doesn't mean be selfish); (2) Don't give too much too early, make them prove they are worth it first (which if they ARE interested, they will love to prove they are); (3) women are typically in the driver's seat on how a relationship progresses, even if they don't realize it (so don't rush it); and (4) when things don't work out with one girl, its just freeing you up to try it things out with another.
Finally, people change. Sometimes its because of issues in the relationship, sometimes it has nothing to do with the relationship. That change may mean they feel they don't feel the same about the relationship. Sometimes these changes happen early on, sometimes after decades of marriage. If she didn't cheat on you, or stab you with a knife, then she probably isn't a bad person, but definitely not one you need to waste any more of your time on either. Chemistry is a powerful thing, and the loss of what you thought you had can be a powerful thing, however:
There are about 7 billion people on this planet. Over half are women. You are probably compatible with at least million of them. Go give some of them a try.
As my best friend's grandma used to say, "Pussy makes the world go around." It literally drives just about every decision men make. If there was no pussy, we'd probably be unemployed slobs watching football 24 hours a day. But thankfully there is, so we do everything we can to get the best of it we can, careers, cars, etc etc. Its all to impress them. Its no different than what happens in the animal kingdom. Its all just a game really, and most of the time a lot of it is out of your control. Some women will drool over you for doing nothing, others will want nothing to do with you no matter what you do. And the same applies to them. Don't take the grand scheme of it so personal or feel hopeless. There is someone out there for everyone. Just have to cut through the weeds to find them sometimes.
And go through a lot of trial and error too.
Best of luck! And keep your chin up.
MOD NOTE: The misogyny in this post is pretty terrible. Rather than delete it, we'll just note that we don't condone this, and count on the community to shun the behavior as well. Cheers!