There may seem to be no gaps at all in which you can catch a glimpse of your breath.
Finally, the last part of the practice is working with thoughts. As you sit practicing, you will notice that thoughts arise. Sometimes there are a great many thoughts, overlapping one over the next: memories, plans for the future, fantasies, snatches of jingles from TV commercials. There may seem to be no gaps at all in which you can catch a glimpse of your breath. That's not uncommon, especially if you're new to meditation. Just notice what happens.