Do the fiancée and fiancé feel a sense of unease toward each other a month after the engagement?

Do not hasten to interpret what you feel as sorcery, possession, or the evil eye. However, if you fear such, resort to Ruqyah Shar'iyyah (Islamic exorcism). It is best for a Muslim to perform Ruqyah upon themselves. If they need to seek help from others, they should seek out people of goodness and uprightness and beware of charlatans.