to be unsure whether one is sleepy or will be able to count on sleeping (see Molina, who puts this in the first person)
Alonso de Molina:
aoc nocochiz nicmati. (pret. aoc nocochiz onicma.) no tener ya cuenta conel sueño. o con el dormir. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 6v. col. 1. Thanks to Joe Campbell for providing the transcription.