Seeing a ghost in your dream may represent someone from your past who you feel is still haunting you. Alternatively, the ghost may be warning you of a danger or warning you about something that's going to happen in the future. In some cases, seeing a ghost could indicate that someone close to you has passed away and they are still watching over you.
It could also indicate that you're feeling lost or like you don't have a place in the world. In some cases, a ghost may be trying to tell you to seek help or tell you something important.
Whatever the reason, seeing a ghost in your dream is often an indicator of something that's bothering you or that you need to address. If you're having trouble sleeping because of this issue, it might be helpful to talk to a therapist about it.
This is my interpretation of what it means to dream of a ghost. At times, the best interpreter of a dream is the person who had the dream. Always keep your own life and nuances in mind when trying to determine what you think a dream might mean, or if it meant anything at all.