Learning to draw -- Day 14

Today was a mix of frustration and happiness. I was having an awful day drawing and just couldn't get any faces to look correct at all when placed at odd angles. I spent the next hour measuring my own face trying to get used to the distances between each feature and scribbled it down into the odd looking picture in the top right. The main thing that was throwing me off was how long to make the vertical jaw bone that comes down off the ear (before it goes horizontal and runs along the bottom of the teeth), which I would usually make too long, which made the rest of the jaw bone too long, which made the whole face too long, which resulted in a face which was ugly as sin. Once I got some measurements figured out in my head, I found out that the distance between the bottom of your ear to the bottom of that jaw bone is equal to half the height between the bottom of your nose and your chin. Once I had this working a bit better I found everything else kinda fell into place (most of the angles I drew here were ones I was having the most trouble with previously). The pages I filled up with drawings before that, which I didn't scan in, are utterly horrible. While I was drawing my mother caught sight of them and proceeded to convince me I was not her son; which is impressive considering I don't actually live with her.

The two pictures at the bottom though were what caused me to go back from happiness to frustration again. I cannot for the life of me figure out how to draw someone with their head tipped back. The jaw always ends up looking like a bucket of crap drawn from the wrong angle and never ends up looking like anything even resembling a face. I figured now that I was getting an idea of the spacing of facial features I could draw them ok but it quickly all fell apart, signified by the little angry face I drew. If anyone has any tips on drawing heads in a tipped back position, please feel free to leave some advice through the comments section.