There are not really symptoms of panic disorder.
Let me clarify by stating the diagnoses of disorder is normally made when someone has experienced continual episodes of panic attacks over a sustained period of time.
Many people will suffer a panic attack one or a couple of times due to a high level of anxiety for a short period of time that subside.
The symptoms of panic attack are varied and different people will experience one or more of these symptoms.
Generally panic attacks will make you feel like:

• You're losing control
• You're going crazy or losing your mind
• You're having a heart attack
• You're going to die
• Something "bad" is going to happen

A general sequence of events will occur when experiencing a panic episode and it usually starts with the feeling that something bad is about to happen and follows with the fear associated with that thought.
Next will come the "fight or flight" sensation that is a sudden rush of adrenaline caused by the body reacting to the fear.
As these thoughts intensify you you begin to feel the loss of control and followed by full blown panic.
Some of the common symptoms associated with panic attacks are:

• Racing, pounding or skipping heartbeat
• Chest pain, pressure or discomfort
• Breathelessness
• Choking sensation
• Excessive sweating
• Nausea
• light headedness
• dizzyness
• Hot Flashes
• Shaking
• Trembling

Understanding there is a difference between a single event and a disorder can help ease your mind when it comes to panic attacks and disorder.
If you are experiencing a intense period of stress in any aspect your life this can cause a high level of anxiety and trigger an attack.
Normally when the stress is eliminated the anxiety will be as well.
If you have experienced multiple episodes then it is probably a good idea to seek some sort of treatment.