I'm sorry to hear that your cough is still severe and accompanied by brown or green phlegm and a heavy feeling in your head. These symptoms suggest that there might be an ongoing infection or inflammation, possibly involving your sinuses or lungs.

Here are some important points and recommendations:

• Persistent cough with colored phlegm can indicate a bacterial infection or sinus involvement that may require further evaluation.
• Since you have been taking Amoxyclav (an antibiotic) and your cold has improved but cough persists, it is important not to self-medicate further or extend antibiotics without medical advice.
• The heavy feeling in your head could be related to sinus congestion or infection.
• You should consult a pulmonologist (lung specialist) or an ear, nose, and throat (ENT) specialist promptly for a thorough examination.
• They may recommend diagnostic tests such as a chest X-ray or sinus imaging to identify the cause and guide appropriate treatment.
• If you develop symptoms like high fever, difficulty breathing, chest pain, or worsening headache, seek emergency care immediately.

Please arrange to see a specialist doctor soon to get a proper assessment and tailored treatment. If symptoms worsen or you feel very unwell, do not hesitate to visit the emergency department.To narrow down potential causes, we will need some more information.I understand you've been dealing with a cold and cough for the past six days. Could you please share your age and gender?