It is not unusual baby has a fever of 39-40 C. All the medication like Tylenol just reduce the sympton to make baby feel better, but not to kill the virus or other problem cause the fever. So even you give her Tylenol, the fever will come back. Tylenol is given every 4 hours. If Tylenol does not work, then switch to Advil. That's what the doctor in CHEO told me. After a couple days, baby will be better. Fever is because the body is working hard to battle the virus.
I always bring my son to the doctor in case like this. This is to make sure nothing more serious is going on.
Always read the label on Tylenol or other medication (the baby ones). Do not give more that what it should be based on age or weight.
I recommend going to your baby's pediatrition. Not that all walk-ins are not good. Walk-ins are not expert on young children. Sometimes they give antibiotic when it is not necessary.