Body is not interested in meditation.  Neither is nature that made this body.  We weren’t built to meditate.  Thus, to meditate is to transcend our nature.  Here’s a relevant passage from Paul Ekman.

“Breathing we never think about. What we are doing with these meditative practices, such as focusing on the breath, is creating skills that in some sense we do not need.  It is very hard to focus attention on our breath because it is automatic.  We are not equipped by nature to focus on it: it is unnecessary.  But if we learn how to do so, then we are more generally acquiring the ability to monitor automatic mental processes and that means we are building neural connections for monitoring what occurs without consciousness.”

When closing your eyes to watch your breath, accept that you are swimming upstream.