How can one overcome insomnia and the fear of sleeping alone at night, especially with marriage approaching, after a previous experience of physical and psychological symptoms related to fear for one's mother?

Humble yourself before Allah Almighty and break before Him, for He answers the supplication of the distressed and removes evil. Adhere to reliance upon Him, for He is sufficient for whoever relies upon Him. Increase in the remembrance of Allah so that hearts may find tranquility, and be diligent in performing ruqyah (Islamic exorcism), for it is among the most beneficial remedies. It is also important to present yourself to trustworthy specialist doctors.