Hardy's developed separation anxiety

Hardy attended his 5th AKC Puppy Star class today - next week will be the test and an opportunity to play "Show and Tell" with 3 tricks we're supposed to work on this week.
He did very well with all the exercises - "leave it" with something on the floor (we've been practicing with our cats); eye contact; sit and down stays (Hardy shifted position but never got up from the stay); loose leash walking and playing around on the agility and flyball equipment. He walked through the ladder nicely with good control over his hind end; went through the short tunnel; got up on the table and sat and downed; and jumped up on the flyball box. He had a chance to play with Pete and had a great time! 

Then, we practiced the separation part of the CGC test and discovered that right now Hardy isn't a big fan of being out-of-sight from us. A couple weeks ago, we worked on it and he couldn't have cared less but now, he is somewhat concerned and whinny about it. Apparently, we need to work on that some more right now!