You sound like a friend who cares. When I'm angry with someone, a friend, for instance, but also care about the relationship, I feel the same way - trying to find a way to express my feelings and concerns to them in a way that won't be full of my anger. What about...doing the opposite? So like when you talk to her, say it with gentleness, and telling her you value her friendship a lot, and then asking for what you would like from her. Its important to you and your needs are valid. I think its also natural in long term friendships, relationships, etc, to have conflict. I think its awesome that you are looking for a healthy and kind way to approach this.