:salam2:
Here's some advice regarding sleeping:
1. Sleep in a state of taharah (purity).
Ibn Abbas reported that Allaah's Messenger said: “Purify these bodies and Allaah will purify you, for there is no slave who goes to sleep in a state of purity but an Angel spends the night with him, and every time he turns over, [the Angel] says, 'O Allah! Forgive Your slave, for he went to bed in a state of purity.'” [Reported by at-Tabaranee. See Saheeh al-Jamee (3831)]
2. Sleep early.
Sleeping early is a healthy habit and it was the practice of Allaah's Messenger to sleep directly after performing the Isha prayer. Abu Barzah al-Aslami said that the Prophet used to prefer to delay Isha, and he did not like to sleep before it or talk after it.” [Saheeh al-Bukharee]
3. Clean the bed and lie on the right side.
Abu Hurayrah reported: The Prophet said: “When any one of you goes to bed, let him clear his bed by hitting it with his garment, for he does not know what may have come onto it. Then let him lie down on his right side…” [Saheeh al-Bukharee and Saheeh Muslim]
4. Reciting the Adhkaar (supplications) mentioned in the Sunnah before sleeping.
There are a number of Adhkaar prescribed in the Sunnah before going to bed, amongst them are reciting the last verses of Surah Al-Baqarah Verse 285 and Verse 286], reciting Surah Al-Falaq, Surah An-Nas and Surah Al-Ikhlas , blow in the palms and wipe as much of the body possible, starting from the head, face and then the front of the body doing it three times. [Saheeh al-Bukharee and Saheeh Muslim]
Also read Ayatul-Kurseey[Al-Baqarah 255].
Aslo concerning mightmares:
Jabir narrated that the messenger of Allah
said, “When someone sees unpleasant dreams, he should spit to his left three times should seek refuge in Allah from the outcast Shaitan. Then he should turn to the other side of his sleep”.
(Reported by Muslim,Abu Dawood,Nasaee and Ibn Majah).
Insha'Allah this helps.
wasalaam.