Brief Answer:
follow the advice...observe how you stay afterwards...

Detailed Answer:
Hello there,
Welcome to 'Ask A Doctor' service...
I've gone through your query in details...
I can understand your concerns...

Well, it seems like along with sinus infection there's some mid-inner ear involvement also (it's possible as it's inter-communicated and such infection and secretions can migrate causing further swelling in the mid/inner ear)...

First of all, start taking steam inhalation three times daily, and do lukewarm salt water gargling twice daily...

Avoid any form of cold-drinks, dairy products and sour foods as they can further aggravate this situation...take an antacid daily (eg. Pantoprazole/Omeprazole etc.)...

Please drink a lot of fluids. Have plenty of warm liquids (soups, broth, porridge etc.), they'll act as an immunity booster and fasten the recovery.

Along with it, you should take a decongestant, eg. Phenylephrine (eg. Sudafed PE three times daily for the next 2-3days), you may need a prescription from your doctor for this.

If despite following this, there's no improvement within a couple of hours, then I'd recommend getting an ENT check-up for further evaluation. Based on the findings, the ENT may advise a Chest X-ray, revise the antibiotics, as well as to take some anti-vertigo medications (namely Betahistine) for a few days.

Let me know if I can assist you further.

Take Care
Kind Regards

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