I have an old friend from way back when that I have contact with from time to time. I too struggle with not remembering things that she talks about. It hurts my friend that I don't remember things that happened. She feels like its because she wasn't "important enough to remember". It just confuses me. I know why I don't remember (because I had did - duh!) but it still amazes me that this really is a thing. I guess I don't remember what I don't remember so I am unaware of the extent of my own amnesia.
I can't say if it will be good for you to contact your friend or not, but it might help validate your amnesia or help you make sense of the fragments. It is a pretty big thing to not remember being a bridesmaid at her wedding. Most people would remember something like that (very nearly all people, I would say). I don't remember some things like that too. Its as though they didn't happen at all. So when someone else talks about them and I trust they are telling the truth but I really don't remember anything about it at all it helps me realize that... there is this thing going on with me and it is real.