First of all, sorry to hear about your breakup dude, i have had a rough breakup myself and it's hard. Especially when she's the extrovert person in the relationship, i don't think she didn't care though. I don't know about your fight, but when time passes, she'll probably think back on the good times and misses you.
If i can give you a piece of advice to feel less bad, when you think about these good times, don't think of it like: I miss that, i want that with her again.
What i started to live by is: Don't cry that it's over, be happy it happened.
Try to remember your time with this girl as a great time, be thankful for your memories and move on.
What i did after my breakup is a lot like you did, i read the game, started reading internet posts and forums, started working on my inner game, my looks. My whole style changed and i started just talking to random people, not just girls, but also the old man in the tobacco store or the granny in the supermarket. It made me more confident talking to strangers, but made me realize it's very easy to charm people. Girls can sense that you're not giving them your full attention, if you are still beating yourself up over your ex, it will influence the way you talk, your body language will be less confident and you'll probably come across too strong or too weak. I don't think you should force this, the talking part requires me to feel good about myself, i'm more spontanious and energetic and girls will sense that you're feeling good.
My personal advice would be to start things easy, you are obviously still getting over this girls. Just give yourself some time to deal with that, in meanwhile, try talking to stranger or girls just as friends. You'll start to feel that people actually like you and it makes it easier for you to get over this relationship. When you are feeling more confident, the moment just comes that you can make your move again. You'll feel it, like instinct. Or at least that's what happened for me, but i'd give it some more time to get past this phase.
Good luck bro, i hope this helped maybe a little
Cheers!