There is no need to go to doctor for a flu/cold because those things go away on their own right?

Not all the times, a cold / flu aren’t minor illnesses, cause it can be severely unless it’s minor then no but all you need to do is go to a GP and check

You can only take something like Tamiflu if you’ve been sick for <48 hours. Otherwise, it’s supportive treatment with cough medication, nasal decongestants, Tylenol/NSAIDs for aches/pains and fevers. If your symptoms go on >1 week or acutely worsen (severe nausea/vomiting, diarrhea, shortness of breath, new onset rash, persistently high fevers >102) I’d recommend making an appointment to see your PCP.

The flu usually lasts five to seven days but your milage may vary.

They can't give you anything to get rid of it. They can only help with symptoms. I have been sick a few days. I wanted to make sure I didn't have strep. I didn't. Just a virus so antibiotics wouldn't do me any good. They did suggest a steroid though to reduce inflammation. It would help my coughing and congestion.

Wrong, many people die every year from complications arising from the flu, you may end up needing breathing treatments, or something else.

It depends now if you don't go to doctor for weeks and then you get to know it's pneumonia, What are you gonna do then

do you have a fever? they have anti virials for the flu. you need to get in when you first get the flu though.