Winston's dream is about his mother and sister. He dreams that his mother and sister are on some kind of ship. The ship is sinking, and Winston knows that they are going to die on board that vessel. Winston is watching this from an outside view because he himself is not on the ship (he is somewhere sunny and nice and safe), but still able to watch them die.
"He was out in the light and air while they were being sucked down to death, and they were down there because he was up here. He knew it and they knew it, and he could see the knowledge in their faces."
The dream is symbolic of his guilt. The reader learns that as a boy Winston took more food than was his ration amount. On one particular day, he took extra food, his mother protested, but he still took it and ran out of the house. That was the last he saw of them. Winston feels guilty that his selfishness somehow played a part in their disappearance, and the dream is a representation of that.
The other dream has a man who tells Winston that they will "meet in a place where there is not darkness." Winston believes it is the voice of O'Brien. There is also a dream sequence about a dark-haired woman that runs naked toward Winston in an act of freedom and Party defiance.