Thank you for your query to DoctorSpring.com
During the winter season, viruses run rampant and are the main cause for common colds.
From your described symptoms, it is a possibility you could have either the flu (due to influenza A or B virus) or a cold virus (rhinovirus from your brother). Symptoms alone cannot tell which of the two is the culprit.
Have you taken your yearly flu shot? If you haven't I would strongly recommend you to get one immeditaely (within a day) which can be gotten without a prescription. It cannot substitute treatment with tamiflu.
However tamiflu cannot be obtained without a precription. Even if you have the flu, all you need is plenty of fluids and bed rest and tamiflu can be precribed if you see a physician within 2 days of onset of symptoms. It is given to reduce the duration of symptoms.
Hope this helps, feel free to discuss further