Can Nyquil Be Taken Instead Of Steroid Shot For Pneumonia?

I was given a steroid shot at 10am this morning when it was discovered that I have potential pneumonia. I was also proscribed an inhaler and a strong antibiotic, both of which I am now actively taking as directed. The Dr offered a cough syrup with codeine for assistance with sleeping through the symptoms that have been interfering with my ability to sleep, which I declined due to being someone who never takes medications at all and fear of having so much in my system at once. The Dr. clarified that Nyquil would be just fine if needed and if I m more comfortable with. I m having some anticipated potential insomnia from the steroid, and some heart palpitations, and I have an irregular heart palpitations to begin with. I feel inclined to take the Nyquil to ensure I get desperately needed sleep, but am concerned with all that is on board, etc. Definitive guidance would be so greatly appreciated, thank you in advance!