Anapanasati: Mindful Breathing Concentration Point

I have been practicing mindfulness of breathing for some time. But I am having doubt regarding my practice. When I focus on a single point on nostril and keep attention there, and note natural breathing. It breaks attention. It seems like there are two objects to concentrate. feel on nostril or breathing? What am I doing wrong? > "He breathes in experiencing the whole body, he breathes out > experiencing the whole body": that is, with well-placed mindfulness, > he sees the beginning, the middle and the end of the two phases, the > in-breath and the out-breath. As he practices watching the in-breath > and the out breath with mindfulness, he calms down and tranquilizes > the two functions of in breathing and out-breathing. Meditation on Breathing