What Causes Raspy Voice After Catching Flu?

HI, I live in No. Cal, I had travelled Jan 31 and caught that super flu bug, which caused me to loose my voice, went into a sinus infection , then lung infection and bronchitis. Took several weeks but I recovered with the exception of my vocal cords which are still not back to normal, my voice is raspy and it wanes as the day passes. I am a bnon- smoker, no allergies, excellent health. What could it be?