I just went to a clinic yesterday she said i have the flu. but i am having problems breathing can't get up and do stuff without being exhausted and i have a pain in my back around rib area that hurts when i cough. what do i do?

Flu can be severe: If you're having such severe symptoms, you need to go back and have your oxygen levels checked. Particularly the test that we call an 'ambulatory pulse ox' - they need to walk you and see what your oxygen levels drop to. Based on that, you may need to be hospitalized. I suspect also you've injured one of the small muscles that connects the ribs (from coughing). Flu can be very dangerous. Go to ER