I understand - I'm much the same, I don't share or express myself as much as I perhaps should. I think this probably comes with the territory for people with dissociative or anxiety related problems. It's not just that we're reluctant to share with others, we compartmentalise and seperate our feelings away from ourselves - hardly surprising that we find it difficult to share with others.
That said, I think discussing these things with your friends and/or therapists would be beneficial for you - I get that you feel you don't want to burden your friends, but I'm sure if they care about you they'd want to listen to you. Personally I would say part of friendship is being there during the hard times as well as the good times.
Music therapy sounds interesting - does music help you express yourself? I notice you post a lot in the music thread here.
I think everybody needs something like that to allow an outlet, and to become invested in - some people do it with music, some people paint pictures, some people collect Elvis figurines - it doesn't really matter what it is. It's possible to channel negative feelings and frustration into something constructive as opposed to destructive.
Hope you're feeling somewhat better