Mania and hypomania are stages of bipolar disorder distinguished by elevated "highs" in mood and behavior that are in stark contrast to the depressive "lows" of the emotional cycle. Mania is a type I bipolar disorder, in which the mood state is abnormally intensified and followed by hyperactivity and a reduced need for sleep.
The presence of one or two symptoms of mania doesn't inevitably mean that you have bipolar disorder. There could be other explanations for your sudden change in mood, including emotional trauma, a brain injury, a drug effect, or an undiagnosed anxiety disorder.
Bipolar mania can be characterized by some or all of the following features:
Changes in thought patterns
Development of psychosis
Sudden changes in energy and activity
You wouldn't necessarily have all of these signs to be diagnosed as manic or hypomanic. To better understand the nature of these symptoms, you would need to explore the root behaviors that define bipolar mania.
According to the Diagnostic and Statistical Manual of Mental Disorders (DSM), bipolar mania can be diagnosed if you encounter at least three of the following symptoms for no less than a week:
An increased interest in goal-oriented activities
An increased pursuit of risky or dangerous activities
Being easily distracted
Flight of ideas
Increased rate of speech
Reduced need for sleep
Psychomotor agitation (such as pacing or hand-wringing)