Acute Bronchitis: This condition is characterized by inflammation of the bronchial tubes, often resulting from a viral infection. Symptoms include cough, chest congestion, and sometimes sinus drainage, aligning closely with the patient's presentation. Weakness can also be a symptom due to the body's response to the infection.

Sinusitis: An infection or inflammation of the sinuses can cause sinus drainage, and if the infection spreads to the lungs, it can lead to chest congestion. Weakness is a common accompanying symptom due to the infection and potential fever.
Influenza (Flu): The flu is a viral infection that can cause a range of symptoms including sinus drainage, chest congestion, and significant weakness or fatigue. It's a common condition that matches the patient's symptoms closely.
Pneumonia: Although more severe, pneumonia can present with chest congestion, cough, and if the pneumonia is due to an extension of a sinus infection, sinus drainage. Weakness is also a symptom due to the severity of the infection.

Pulmonary Embolism: While less likely, a pulmonary embolism (a blood clot in the lungs) can cause sudden onset of chest congestion and weakness. It's critical to consider this diagnosis due to its high mortality rate if not promptly treated.
Heart Failure: Exacerbation of heart failure can lead to fluid buildup in the lungs (congestive heart failure), causing chest congestion and weakness. Although less directly related to sinus drainage, it's a critical condition not to miss.
Tuberculosis (TB): TB is a bacterial infection that primarily affects the lungs but can spread to other parts of the body. It can cause a chronic cough, chest congestion, and systemic symptoms like weakness. Although less common, TB is a critical diagnosis not to miss due to its public health implications and the need for specific treatment.

Sarcoidosis: A condition characterized by the growth of granulomas (inflammatory cells) in various parts of the body, including the lungs and sinuses. It can cause a wide range of symptoms including chest congestion, sinus drainage, and systemic symptoms like weakness.
Histoplasmosis: A fungal infection that can cause lung symptoms similar to pneumonia, including chest congestion, and can also involve the sinuses. It's more common in certain geographic areas and in individuals with specific exposures.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can affect various parts of the body, including the lungs and sinuses, causing a range of symptoms including chest congestion, sinus drainage, and systemic weakness.