Are you having them a lot?
Have you had them before?
What are your symptoms?
Sorry for the questions but there are differing symptoms which are all indicators of panic attacks and some people consider shortness of breath a classic sign whereas others may have stranger symptoms and not realise they are suffering. You may be helping someone else out here too!
I used to suffer terribly with attacks when I was in the depths of depression. I found out how to get rid of the trigger and once I did that the attacks disappeared remarkably quickly, although the other day I still had that feeling start up within me. It's almost for me like a feeling of fear spreading over me. I get deja vous and I would panic. This was always tied up with over tiredness. The more you panic about panic the worse it gets but it is easily treatible like others have said.
Look at all the stresses in your life, write them down and talk to someone you trust or talk to your GP as soon as you can. Don't be afraid to do this as there are thousands upon thousands of people right now suffering with painic attacks across the country.
If yours have come on suddenly then they are likely to go suddenly. If you feel one coming on, try the paper bag trick, it can help some people, if not then I used to keep telling myself "I will get through this, it will go away". And it AWLAYS did. Sadly talking from experience I do understand and so do many others.