I've had this one too. As a child I used to be obsessed with my breathing fearing I'd never get my mind out of it. Of course this wasn't the case. I soon dropped the whole obsession and my breathing felt normal again.
I've also been obsessed with many other bodily functions. What I've learned is that obsession is kept alive by a set of beliefs and compulsive behavior. Have you ever thought that it isn't dangerous to be occupied with your breath. Many meditators would be jealous if they heard you spend all your time focusing on your breathing
It might feel bothersome but it's like that only because you believe focusing on your breath means something catastrophical. I suppose you do a lot of avoidance and other compulsive behaviors trying to get rid of that thought? Find out what your compulsions are and start to cut them out. Don't fight the obsession. Fight the compulsions. You can still do all the things you value with having the focus on your breath.