I have major panic attacks for no reason what can I do to stop them?
When you feel your about to have one just RELAX & remember to breathe. If the problem is THAT serious I would suggest going to a doctor & explaining to him your problem.
Goodluck :)
Also this might help you
http://www.anxietypanicattackhelp.com/How-To-Stop-A-Panic-Attack.php
you should try meditating, I know it can sound stupid but it is quite soothing lol