Stop taking rejection personally unless she is being openly disrespectful

Not every sign of disinterest is a personal attack, and conflating the two will make you overly sensitive and reactive in ways that hurt you. If a girl simply stops talking to you, that is not disrespect. It is just a lack of interest. You should not tolerate genuine disrespect or insults, but a woman withdrawing or declining to engage is not the same thing. Getting bitter or resentful over that kind of normal rejection is not justified. The advice here is direct: stop being that sensitive about it, because in the larger scheme of things, it simply is not that important.