If you can't find a specific trigger for your attacks, it's possibly time to have a look at your life and figure out what you need to change. They can be indicative of something you are not happy with in your lifestyle. You say you have it all together, is that rationally, emotionally, or both? Also, when they went away last time, what had you changed, if anything?
If thinking about those things still doesn't help, pay a visit to your doctor to make sure there's nothing chemically wrong.
Good luck
