What could be wrong with my 4 yr old son? ?

For the past two days my son has ran a slight fever of 100 off and on accompanied by a mild constant cough. Today his eyes began to get goopy and bloodshot. I took him to the Dr. and he told me that he has a touch of phenomena. He prescribed an antibiotic and some codiene to help him sleep at night. After leaving the office I couldn't help but feel that he was misdiagnosed. As the day has progressed his temps have raised to 101.5 and can't stomach any food. His cough has worsened and his throat is raspy. His eyes have gotten puffier with a constant film of goo and seems extremely fatigued. Its Friday night and my only option now is to take him to the emergency room. My 6 year old son is now showing the same signs and its only a matter of time before he has it full force. Just wondering if anyone has experienced anything like this or would have any ideas on what this could be before I take the next step by taking him to the emergency room. I can't take seeing my little ones so miserable! Thanks for your comments in advanced!