Yep - my first 4 weeks, I just hated the feeling of air getting forced into my airways. And then 2 weeks ago, it flipped on a dime ... I guess my brain decided "this is what sleepy-time breathing feels like", and now it's a very relaxing sensation.

It all makes some sense, I think - it would be bad, evolutionarily, if we couldn't get used to the sensation of breathing, even if it happens to be slightly weird for whatever reason.