Is the languor in studies, weakness in resolve and faith, and delay in performing obligatory duties that the questioner is experiencing due to being afflicted by the evil eye or magic, or is it merely a whisper [from Satan], and are these symptoms normal?

It is not possible to definitively diagnose the condition, but ruqyah (Islamic exorcism/healing) is prescribed for one who imagines himself to be bewitched, possessed by jinn, or afflicted by the evil eye, just as it is prescribed for one who has not been afflicted by such things.