A ton of pent up anger....? : \?

Last night, my best friend and I had a huge talk about all the fighting we've been doing the past year. We both personally felt betrayed and hurt by the other. We spent a few hours discussing what we'd done to hurt eachother, and promised to make a fresh start and how much we still cared about each other. It made me feel really good, and today when we hung out it was like we were new friends; we spent the whole day laughing and swimming and talking and running all over the place. But deep inside me, I can still feel a lot of the pain and anger I felt by his betrayals this past year. Is that normal, even though we made up?? How can I release some of this? We've already talked about it, and I feel good about what was said, but I want to know how I can let all of this go. It's very difficult for me.