How will anyone care about your characters if they don't come alive. Let's face it. We use what we know to breathe life into our characters. No one cares about a two dimensional character. Yes, she has anger issues so what. Give her a past. Every guy she has ever loved has betrayed her in one way or another. Of course she's always angry, especially when the class A jerk comes sniffing around her. Turns out he's not exactly a jerk, just has his own broken heart to deal with. Give your characters depth. Take from experience.
The anger you felt clawing at you when you found out your best friend hurt you-use it to your advantage. Remember it and apply it to your character. How does it feel to have anger build up within you? You know. So put it on paper; make us care about the character. Make us give a damn. It's up to you. You have the tools and the understanding of what creates a memorable person; one readers can truly care about. So use your experience and just do it.