I can so relate to this! I have SPD and Auditory Processing Disorder, and I can't follow a conversation more than the trivial and mundane. Don't bother to ask for my input; if I even managed to understand the conversation, my thoughts don't come out quite right (sometimes, it's just not what I meant; other times, it's down right nonsensical).

The worst part is that no one believes or understands the problem. I have a twin sister who is deaf. She can't hear anything other than some environmental sounds. And she has an audiogram that proves it. At most, all I have is a confused look on my face or a strange response. People are always saying, "You can hear just fine." But I can't. And I know from experience that you only get so many "What?"s and "Can you repeat that?"s before people get frustrated with you. It's easier to just wait for more clues or tell yourself that it wasn't that important anyways. So people take your silence to mean that you heard, understood, and agree with everything they said, reinforcing their belief that you can hear 'just fine'.

And if they do believe you, they still don't understand how much it really affects you. They think that you would only have a problem at a loud club or concert, like they would; they don't consider a busy (as in not closed) mall or restaurant, a full business meeting or classroom, or even a quiet office (if you are tired and overstimulated enough). They don't realize that it is more of a problem in a business setting where most communication is through meetings than in a school setting where with textbooks and research you can get most of the information anyway. So those good grades you got from constant studying proved (to them) that you can hear and should have no problems (in a completely different setting!) at work. And most businesses that you work for or with (as a customer) require you to use the phone as the first, if not only, resort in communication.