Well if you say you had 100% breathing during the night but still coudnt ended up to sleep. The issue of not sleeping was then probably related to anxiety/stress/thoughts or even anticipation of having bad sleep. In other words like insomnia. Its a bit weird that in under an hour you get can go from worst mood to happy & excited. Going from worst mood too normal/not so bad in under an hour would be more realistic. Do you have moods problem or mood disorders? It could also be be the nasal cycle like you mentionned. Different situations/environnements affect the nose thus our breathing. For example, I can tell when I take hot baths that im more aware of my nose cycle (one nostril completely block while the other opens more then it was originally). This lead to me breathing mostly from one side which is too open (more then normally) and leads to poor breathing/hyperventilation and huge discomfort. That can then also leads to anxiety/frustration and not being able to relax while taking a bath (which should be relaxing in theory). Note that its mostly impossible for us to fully relax but you get the point.