I feel like this all the time. I can be lonely in a room full of my closest friends. I can sit through an entire conversation, even engage in it, and never know what I'm saying or remember later what was discussed. I see everything through a filter and find myself wondering why I am so different from all of these people and why I can't feel normal for very long. I suppose this isn't very supportive, but I do understand and you are not alone.

"A wise man leaves the road, and finds the way."
- Lao Tse