More than anything else, anxiety is the embodiment of "give it an inch and it will take a mile." OK, lets say you cancel this vacation - because of a diagnosis you don't have - where does it end? How much more of your life will you cede to your anxiety?
Also, a bit harsh so I apologize in advance, but the title of your post is "Should i cancel our vacation" not your vacation but our vacation. Why would you deprive your family of their vacation and pleasant memories to feed your anxiety seems a might tad on the selfish side.
I truly hope you take the first step towards beating anxiety by not letting it steal your family's vacation.
Best of luck