Kind of off-topic, but one thing you might want to try with Austin at the vet is classical conditioning - basically, click/treat continually while he's in a 'scary' situation so that he starts to associate that sitaution with Good Things for Austin. It will take time, and you'd need to do it more often than just his regular check-ups. You might have to start in the parking lot, if he gets nervous there first - click/treat as soon as he can see the building (or, if it's not until he's in the building that he starts to get anxious, as soon as he gets in the door), and keep c/t'ing until for a split second he looks for the treat after you click. Jackpot!! (Lots of treats) Praise and go home. Come back later or the next day - he'll start looking for the treat sooner and sooner, until he's paying attention to you instead of worrying about being at the vet. Then start getting him further into the clinic, into the exam room, introducing the vet tech, the vet, etc. All of this one at a time, very slowly, don't add new things until he's comfortable with the level he's at. When you start introducing the people, start with them just in sight and gradually closer. As they get in range, they can start tossing him treats after you click.
Of course, since he did so much better with you gone, maybe it's not his nervousness at all, but him picking up on yours. Next time you should take the valium!
