Friendship and self esteem

Lately I've been feeling really small and just bad. I've been trying to be more confident so I've been more strongly defended myself and my opinions. I've found I've been getting mad easier too. My best friend called me and told me she hates to go against me but I've been being way too confident and proud. She says when I think I'm good at something I really strongly show it. I've been thinking Im being kinda aggressive too. I feel small again and really unconfident. Tomorrow I'm going to see her again and don't know what to do. Plus I just need some cheering up and a boost. Can somebody please help?