"Crying yourself to sleep" means... when there're grievances and discontentment, and you're helpless to resolve it — so much so that you want to give up, to fall asleep with those negative feelings. I wonder how many times I cried myself to sleep. To be honest, I used to think that words were just words, but on a night when my heart was breaking apart, everyone's words kindly supported me. Overwhelmed by that kindness, once again my tears overflowed. It sounds a little silly, but thank you, thank you.