Grief is kind of a process. Yes, you may have gone through all the stages in 15 minutes, but that doesn't mean your grieving process is over. The thing about the stages of grief is that they don't need to be in order, they don't all need to happen, and you can go through some of the stages multiple times. You may be fine now, but it may hurt later. That's normal. Take care of yourself through it.

I'm sorry about the loss of your friend.