There are 3 types of dreams : Imam at-Tirmidhi رحمه الله narrates from Muhammad Ibn Sirin رحمه الله who narrates from Abu Hurairah رضي الله تعالى عنه that Prophet صلى الله عليه وسلم said, “There are three types of dreams:
1) True Dreams
2) A dream in which a person is speaking to himself (i.e. whatever you were thinking about in the day time, you see at night)
3) A dream from shaytaan in which he wants to make you sad ”
In one hadith it is said that one should stand up and pray and in another the he should not mention it to anyone.
Abu Salamah رضي الله عنه once said, “Sometimes I would see a dream that would be heavier on me than carrying a mountain. But since I heard this hadith I wouldn’t care about the bad dream I would see.”
Narrated Abu Sa‘id Al-Khudri رضي الله عنه: The Prophet صلى الله عليه و سلم said, “If anyone of you sees a dream that he likes, then it is from Allah, and he should thank Allah for it and narrate it to others; but if he sees something else, i.e., a dream that he dislikes, then it is from Satan, and he should seek refuge with Allah from its evil, and he should not mention it to anybody, for it will not harm him.” [Sahih Muslim]