Re: sore throat, what could this be?
First of all, you need to see a doctor. My doctor gave me a hint to help me determine what type and how serious the condition is. If the sore throat is general pain/irritation in the entire throat and there is not evidence of spots or pus it is probably a result of cold/flu/sinus. If the sore throat is specific to an area in your throat, so specific that you can point to it, it is probably a bacterial infection that requires antibiotics.
In both cases the soreness can be equally painful, cause difficulty swallowing, and either can indicate a more serious condition. You do need to see a doctor to find out if you need antibiotics.
Regarding strep infections, you cannot diagnose this yourself. Strep can be a funny infection with inconsistant symptoms. Several years ago my husband I were both ill for about a week. He had typical strep symptoms (severe sore throat, white spots on throat, fever). I just had a general feeling of flu (fever, aches, pains etc.) but no sore throat. We both went to the doctor and both tested positive for strep... but I NEVER got a sore throat!