When should i see a doctor for a fever, hot throat (probably from the fever), body aches, and bad headaches and nausea?

Infection? Allergies: Preferably as soon as possible. May need Strep throat test & antibiotics.

Maybe strep,flu,etc.: Throat symptoms can be from cold viruses, strep throat, allergies, etc. It may be difficult to tell what the cause is. If symptoms only last 1-2 days, it was likely allergies, irritation, or a mild cold. Doctors have fast 5-minute tests for strep, so a primary care doctor can diagnose strep and start antibiotics "soon", which means within the first 3 days of strep symptoms. Strep may cause nausea.

Possible flu: The symptoms you give sound like the flu and if this is not older than 2 days old, there is a medication you should start. If these symptoms have been going on for a longer time you need to be sure you are not developing a pneumonia or other problem. You should see a doctor now for diagnosis and treatment.