As settings for dreams, these are ambiguous places. It seems as though amusement parks often include elements that we consider to be the best and worst in life.
Many of us have enjoyed these places tremendously, but have also seen, smelled, or actually experienced the consequences of overdoing it: vomiting. Carnivals also include a very wonderful or frightening collection of personalities. These personalities may intimidate us at times. Sometimes the fright comes from a figure we love, such as a parent who doesn't really enjoy the carnival, but endures it for the children.
Eventually, the illusion of the idyllic family outing is transformed to an angry scene. Who are you with in the carnival and how do you experience the time there?
Finally, carnivals are full of out-of-control experiences. Being out of control can be ecstatic and wonderful. In these instances it may remind us of a sexual experience.
However, it can be terrifying to people with fairly rigid waking boundaries. Spinning and riding fast are two chaos images often associated with carnivals. Ferris wheels reflect times to remove oneself from the midway to a quieter perspective, unless one is afraid of heights. In what way are the rides metaphors for your life? In other words, how is your life like a rollercoaster, merry-go-round, or other central feature of the park?
Perhaps there is a ride pronouncedly missing that you want to experience but cannot-what is that a metaphor of and why do you desire it so?