After we broke up she brags about how great everything is.why?

We have been texting for half year now. She always pushed me away. But when i started to move on she always came back flirting and apologizing. Always excuses.like im not ready for relationship.im scared of relationship. And month ago she said she never wanted relationship with me. So i said its over and stopped contacting.but after few days she came back begging and apologizing.and asking me to give her a month to work things out in her life so she can decide if she wants to be with me. I forgave her but said that i can wait but i wont guarantee that i will change my mind. She flirted heavily for few days.but when i started to show interest back she became cold and. Pushed me away. That was the last drop.

I deleted her number and started to search for other girls. And i meet an really interesting girl from same school my ex was. We started texting. Now yesterday my ex texted me asking if im ignoring her.but i just gave her casual answers.Then She asked me about new girl im contacting with(she somehow heard) i said "were doing great :)"

And she got mad. Later her friend texted me asking why she is crying and smashing dishes.but i said i dont know and dont really care anymore.(i think her friend only texted to manipulate saying that my ex do care about me and blah blah!)

So next morning all i see on my exs social networks is how she says that everything is great and perfect. It made me a bit confused that she cried yesterday and now she is so happy.. she is 16 btw and im 18