Just so you know, there are many of us suffering with the same sort of symptoms right now. There is a virus going around that the doctors are calling the 100 day flu. Mine started off that way, then progressed to runny yet stuffed nose, then to thick , sticky phlegm that my lungs can't seem to cough up.
I would still go back to doctor though if your throat is still sore...sore throats can lead to meningitis or other such things. Always better to be safe than sorry.
My sore throat only lasted a few days...anything longer than that is a cause for worry.