hello, i'm a 25 white male, for the past year or so i haven't been able to become fully erect, i'm healthy(as far as i know) 5'10" 180 lbs and in pretty good shape, also i eat healthy with the exception of a few fast food meals hear and there
i'm not sure if this has anything to do with it or if it will help but my penis size is 3" flaccid and 5.5" (semi erect) it used to be 6 when fully erect
i can still have sex but it's just not as firm as it once was
any ideas on how i can correct this?

thank you