This momma needs help! Please

My son is almost two years old and just had gotten over the flu last week. Now he has a 103 fever on and off since Saturday morning. I have done everything from Tylenol to Motrin to pedialite to sponge baths. I went and saw the pediatrician today because he was fine all day and then spiked a 103.7 fever! The doctor said if he is not better by Wednesday he is going for xrays and bloodwork. Now he is coughing up lots of phlegm but he is not throwing up, no diahrea and no boogies.. Does anyone have any clue what this can be! Doctors think it could be pneumonia. Please help this momma out 😓