Shingles are an outbreak of rash or blisters on the skin that is caused by the same virus that causes chicken pox, the varicella zoster-virus. My MIL suffered from shingles later in life and I was her care-giver and did not contact it. I've never heard or knew of shingles being contagious, though I may be mistaken. How about phoning your local Health Dept. or even your pharmicist, if you're hesitant about asking your doctor?
Personally, I would telephone my doctor and ask anyways, and just let him laugh, even if he's that unsensitive to your concerns, at least you'll (hopefully) get your answer and be on your way to Spain. Then I would find another doctor who is more patient-considerant the next time.
Have a wonderful trip to Spain.