Sorry noone replied sooner - I think ppl were at 4th events.
I think your little one has recently left his litter mates and is insecure. He is not sure you are going to come back for him, so he's reminding you. I use a play pen type enclosure and put bed, dishes, and wee pad when pups were young and I could not watch them. My first yorkie, I did crate when I went away until she was 2 and trustworthy. You might want to try a play pen when you are home moving around and just can't be right there to watch. That might cut down on the barking/whining then. I also used a stuffed toy about the same size as the pup as a pseudo-littermate. They do sell "snuggle pups" (on Amazon) that are a stuffed toy w a heartbeat to simulate littermate. Wish you luck. Believe it or not, this time will fly past and you will miss his babytime.