flu season can I take this.

My doc said its ok for me to take Tylenol, Sudafed and robitussin. All three of these ingredients are in DayQuil which is my go to medicine when I'm sick so why didn't she say u can take DayQuil. It actually has less of the dextromethorphan than robitussin. And it really soothes my throat. I don't take nightquil because it has a sleep aid. But DayQuil should be fine right?