Do You Have A Whiny Dog Who Sings The Blues When He Is Lonely?

We have a beagle/basset mix who has always been a super happy go lucky fellow, enjoys life, is very well behaved, prefers to live outside in an indoor outdoor pen, and generally is pretty quiet unless someone comes around. Since we got back from vacation though, he has been HOWLING the blues several hours a day. The doggie day care/kennel he stayed at had lots of other dogs, and he seems like he is lonely and misses them. If we are out in the yard with him, he is his funny, silly old self. He sounds so sad when we aren’t though. From basic dog training, we know not to coddle him when he is misbehaving, but when he isn’t crying, I go out and spend time with him every day. At least an hour, sometimes longer. Should we get him a playmate? We have a house dog and they don’t get along at all. The westie is a total brat and always pushing him around. Broo (the beagle) was at one time a playmate to another of our older dogs who passed away, so could it just be lonliness?