It sounds like you have an acute illnes, and the msart money would be on the flu. Strep can also cause similar symptoms. If you have any pain on urinating, you could have a serious kidny infection. Since you have a stuffy nose, (unless that is a red herring) it makes the flu more likely.
So here's the catch. If it's just a virus, you will probably kick it in a day or two.
If it's strep, you need antibiotics and a simple office based test will give you an answer.
If its the flu, the office based flu test may be able to tell, but these tests are not that great and can miss many cases of the flu.Since it's been 3 das, it is unlikely that tamiflu could give you any benefit. However, if you do have the flu, a secondary pneumonia
is possible, which would require antibiotics.
Given your description of how sick you sound, I would at least go to an urgent care and get looked at, to make sure you do not have anything that is more serious, or something treatable so that you do not needlessly suffer
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