My GP told me I had shingles years ago as I went in with a really sore back and he found a rash when he looked. He had to phone to get authorisation for some special meds (so got me worrying that it was serious stuff) but by the time I'd waited ages, spent heaps at the chemist and gone home, the rash was gone - turns out it was a bit red from the heat pack I'd had there, lol! I changed GP's after that....

So yes, he could have it wrong. I wouldn't be worried if you have no other symptoms.

I wasn't preg at the time, by the way.