Sick Baby? Should I be Worried?

My daughter is almost 14 weeks old (3 months) and has been coughing and has had a runny nose for a bout 2 weeks. At first it was just subtle coughs and a slightly congested nose, but now it's wet and comes in episodes, and no matter how many time I clear out her nose she always has boogies and makes noise when she breathes. She is coughing and throwing up yellow and green mucous. She does not have a fever. She was exposed to my best friend's baby 3 weeks older than her that was having the same symptoms, and now her son has ped away. He was found in his crib with blood on his pajamas and foam coming out his nose and mouth........I'm worried that he might have had something more than a cold and that it may have ped onto my daughter. She slept last night for 11 hours straight and then I woke her up. She only drank 23 ounces today and has slept a total of 18 hours in a 24 hour period. She saw the doctor last week, but they said to give her nose drops, runa humidifier, and call them if it lasted over 2 weeks.....which will be tomorrow....is there anyone out there that might have a clue if the symptoms match something other than a cold that I would need to look out for? Thank you!