What's the difference of a common cold as oppose to sinusitis, allergy meds or puffer doesn't work, conjestion,cough no fever day 3 not getting better?

Timing is important: Many symptoms of a viral upper respiratory infection are similar to symptoms of acute bacterial rhinosinusitis ("sinus infection") - nasal congestion/obstruction, nasal drainage, facial pressure, low-grade fever, etc. Timing of the symptoms is important. If symptoms persist for 10 days or longer, or if symptoms initially improve and then worsen again, it is more likely a bacterial sinus infection.