RE: Leaving my pets for vacation for the first time.
That's a tough one. My dog is of course affected when we leave him on his own for a while, but most of it he takes out with just not pooping; he'll still eat like normal. My biggest suggestion would be to leave some things for your dog that she is familiar with that will remind her of you. We always leave a pet sitter with the animals when we're away, and we've been told most every time that the dog spends more time then he usually does curled up on the pillows that we use, instead of using his bed. We suppose he likes the scent and feels closer to us even when we're away if he has access to things that make him feel more comfortable without us.
Another tip - do you have any people that visit often that your dog is fond of? If so, that person might be the best choice of a pet sitter for you. If you have a friend or family member that your dog really likes being around she might be more comfortable being away from you if she is in the company of someone she is already familiar with; someone she thinks of as part of the family even if they aren't there all the time. My dog is very sad when he is left completely alone without anyone he knows around, but if we call my aunt (who he just adores) to visit him he always perks right up when she's there.