About reading textbooks: you'll get tired, put it away, turn of the light and then can't sleep and is not tired. Turn on light, read again, get tired ... Etc.
Try audiobooks! No need to turn of the light, just listen in the darkness :)
Many audio-book apps have a sleep timer feature, so you don't have to worry about the book playing the whole night if you fall asleep in the meanwhile.
You don't learn anything and you don't sleep.