I remember when I had a panic attack, that suddeness, because of a lot of stress. That unexpectedness can be very frightening. But it doesn't have to happen again, become an "illness" can just be a part of this particular constellation of what's going on with you at this moment. I would try not to start anticipating this happening again and thus set up a expectation that your body tries to fulfill.

If you are normally a calm person and now under a lot of stress, that's all it is; like getting a cold when you're under stress. Stress can cause weird responses; try to shrug and keep working to get through the difficult stuff happening in your life and not get sidetracked by the "show". Your body is trying to tell you you're stressed to the limit and need to take steps to resolve some of it so you don't get more seriously ill.