Feeling haunted by something or someone is a sign of severe restlessness, the cause of which has not yet been discovered by the dreamer. It is possible that feelings of guilt are affecting your sleeping. However, it is also possible you need to face a problem that, so far, you have consciously refused to see.
Gallery of dreams
Do animals dream?
Research conducted by various scientists show that animals do experience dream while sleeping. They also experience similar sleep stages like human beings - REM and Non-REM. If you have noticed a dog sleep, it might sometimes wag its tail, this indicates some response to its dream. A study was conducted in a cat by removing a part of the brain stem, which will not prevent it from reacting to the dream during REM. It was noted in some cats they were aggressively chasing mice as in reality.
Inflammation, it is associated with diabetes, stroke, arthritis, heart disease as well as premature aging. There have been researches showing that people who gets less than six hours of sleep a night have their blood levels higher than those who get more. A study done in 2010 has figured that the C-reactive protein is higher in people who only get a few hours of sleep every night. According to Dr. Rapoport, people suffering from sleep apnea or insomnia could develop high blood pressure as well as inflammation, so treatment of these sleep disorders must be followed.