dog not acting like herself

Question
About a week ago out 9yr old shihtzu started acting strange...not accepting treats, pawing at us, acting scared, won't go outside by herself, won't lay down and falls asleep while standing, goes out into garage and sits by car door, won't let us out of her sight...these are all things that she never did before. We took her to the vet, he did blood workup and found nothing...took xrays and thought she might have some digestive problems and gave us 3days of metacam and metronidazole. It's like we have a different dog. Nothing has changed in her normal daily routine and there has not been any trauma I know of. She does have anxiety during storms, but we haven't had any. How she is acting is similar, but exagerated, to a thunderstorm. Any help you could offer would be greatly appreciated. Thank you!

Answer
I would pursue this further with your vet.  Pawing, acting scared and failure to accept treats may indicate pain or anxiety.  Has anything changed in your household?  Construction in the neighborhood?  Any new sounds?  Recent emergency vehicle activity near the house?  Loud noises?
If not, I would say she may be having pain somewhere: stomach, limbs, mouth/dental problems perhaps.