Roller coaster

1.

An amusement railroad of varying design in which open cars coast by gravity over a long winding track in a closed circuit, with steep pitches and ascents, and in some cases loops in which the cars are briefly upside-down; typically, the cars are pulled by a chain device to the top of the first peak, after which gravity and momentum provide the only propulsive forces. In some cases, the cars are suspended from a monorail rather than resting on a track, and such cars may be made to swing outward at an angle near to the horizontal. It is a popular amusement at many amusement parks, but is sufficiently frightening to some people that they refuse to ride in one.

Noun	1.	roller coaster - anything characterized by abrupt and extreme changes (especially up and down); "the economy has been on a roller coaster all year"
	2.	roller coaster - elevated railway in an amusement park (usually with sharp curves and steep inclines) Synonyms: chute-the-chute, big dipper

To dream that you are riding a roller coaster, signifies that you are experiencing erratic behaviour brought on by yourself or a situation. You are experiencing frequent ups and downs in your waking life.Sturm und Drang, turbulence, upheaval