Should i stay or should i go?

Tell her how you feel, that it hurts you when she yells at you or blames you. Tell her it's making you unhappy. Ask her why she gets angry. Don't argue with her or even defend yourself. Just listen to what she has to say. If everything she says is about her, then maybe she's not right for you. Maybe she's too selfish. If she talks about your feelings, and apologizes and promises to try to do better, then maybe there's hope. You're not being a bad friend if you leave, provided you do it kindly and tell her you're there for her if she gets in a bad way.