Firstly: 

It is not permissible to go to fortunetellers and soothsayers and other such charlatans. Whoever goes to them and asks them about anything, his prayer will not be accepted for forty days, and whoever believes their claim to have knowledge of the unseen or to be able to relieve hardship and bring benefits is a kaafir, as it says in the saheeh ahaadeeth narrated from the Prophet (peace and blessings of Allaah be upon him). 

It is not permissible to use turquoise (as a charm) and amulets. A stern warning is used in the saheeh Sunnah to the one who does that.

It was narrated from ‘Uqbah ibn ‘Aamir al-Juhani that a group of people came to the Messenger of Allaah (peace and blessings of Allaah be upon him), and he accepted the allegiance of nine and refrained from accepting the allegiance of one. They said: “O Messenger of Allaah, you accepted the allegiance of nine and not this one.” He said: “He is wearing an amulet.” He put his hand in and took it off, then he accepted his allegiance, and said: “Whoever uses an amulet has committed shirk (has associated partners with Allaah).” Narrated by Ahmad, 16969. This hadeeth was classed as saheeh by Shaykh al-Albaani in al-Silsilah al-Saheehah, 492. 

In the answer to question no. 10542 you will find the details of the ahaadeeth which have been narrated concerning amulets, and the rulings of the scholars on amulets containing verses from the Qur’aan and amulets consisting of other things. 

In that answer, Shaykh Sulaymaan ibn ‘Abd al-Wahhaab is quoted as saying: 

“This scholarly difference was concerning hanging up amulets which contain Qur’aan or names and attributes of Allaah, so what do you think about the things which were innovated later on, doing spells (ruqyah) using the names of shayaateen (devils) and others and hanging them up, and even being attached to those shayaateen, seeking refuge in them, slaughtering animals for them, asking them to ward off harm and bring benefits – actions which are pure shirk? This is prevalent among many of the people, except for those whom Allaah keeps safe and sound.” 

And Shaykh Haafiz Hukmi said: 

If they (amulets) contain anything other than the two revelations and instead contain mumbo-jumbo from the Jews or worshippers of the temple, stars or angels, or those who use the services of the jinn, etc., or they are made of pearls, strings, iron rings, etc., then this is shirk, i.e., hanging them up or wearing them is shirk, beyond a doubt. 

Secondly: 

In the answer to question no. 9577 you will find some means of protection against nightmares and disturbing dreams. 

And Allaah knows best.