Islamic Interpretation of Dreams (Ibn-i Sirin):
(Doubt) In a dream, uncertainty means heedlessness or being allured by Satan. Uncertainty and doubt about all religions in a dream represents adjuration and ingratitude.
If a person who is concerned about religious explanations sees himself unable to recognize what faith he belongs to, or what direction to turn to in a dream, it represents doubt and lack of knowledge or certitude.
If a seeker or a student on the path sees himself searching at no avail for a place to pray in a dream, it represents a blocking on his path, or obstruction of his learning.
As for a merchant, uncertainty in a dream represents obstacles hindering his efforts from receiving any significant benefits from his business.