You’re exaggerating what happened
You’re also exaggerating what happened – both in your head and in the story you tell others. If a friend flirted with your boyfriend, you say she was carrying on something of an emotional affair with him. If a friend gave you constructive but unsolicited feedback on your work, you say that she basically called your work garbage. If you generally give more than you get from the friendship, you say that this friend has never been there for you in any way or done any favor for you. Ever. (You know that’s not true or else you wouldn’t have carried on the friendship).