Racheal,
Rachealrachealracheal!
If this continues, clonezapam works wonders for me. Never had an issue with anxiety until the wreck years ago. (I should probably post the whole story somewhere). I drank my worries away. ---Not bragging, I'm a recovering alcoholic.
So DUI, many broken bones, and then the delirium tremens hit (drying out). I had to be tied to the bed. I don't remember any of this because of the traumatic brain injury, coma, and morphine drip. (Parents recounted the story for me). So they put me on clonezapam and antibuse and a whole list of pills.
Anyway, all that faded out and I was feeling better until 2 summers ago. Like you said, some symptoms give us no warning. I'd be outside, enjoying the day and
BANG! I would suddenly feel 'crowded' and scatterbrained. Not just cog-fog, something worse than that.
So I go to my PCP, explained that it was happening once a week or so and she put me on 0.5mg of clonezapam. I have since had to bump it up to 1mg a day.
I'm not proud I need ADs and antianxiety, but I'm glad I take them.

If this continues, please get the help you need to keep it in check.