Getting sleepy while doing Rama Raksha Stotra.

So I used to do Rama Raksha Stotra every full moon, but since January I have started doing it daily three times. I got sick a few days ago, so instead of singing it like usual, I did it mentally and have been having a very hard time staying awake while doing it. Could anyone tell me what I could do to avoid this? My throat is still not in a condition to verbally chant.