I want to take Tylenol for my nighttime flu. Or cold/sinus, I don't know if I'm allowed.

It is generally safe to take Tylenol for nighttime flu or cold/sinus symptoms while breastfeeding, but it is important to be cautious. Some decongestants may potentially reduce breast milk production, so it's something to watch out for. If you have thyroid gland issues and take thyroid medication, like Synthroid, you should be extra vigilant when taking decongestants because they can affect your heart rate. Always be mindful of how medications may interact with any health conditions you have.