You most likely have a few side effects from the vaccine if it was recent like coughing or a fever is possible. You can't get sick from the vaccine because it is an inactive vaccination that contains dead influenza viruses. Each year they only do certain strains though because there are many strains of influenza so you could potential get a different strain than the ones you were vaccinated for. I wouldn't worry about it and if it was a virus affecting you you'd just have to wait it out so staying hydrated would be key.