[help] My dog has started to cry in her kennel, every night, and only at night.

Hi, all. My family has a 4.5 year old ACD/catahoula mix. We rescued her off the street about two years ago, and since then she has been sleeping in a kennel in the living room (she is not allowed in any bedrooms in the house and is not allowed on any furniture). She is a nervous dog by nature and likes to be near people, but she has always slept well in her kennel.About five days ago, she started crying loudly in her kennel at about 10:30 PM. I put her out, but by 11:00 she was crying again, so I slept on the couch to keep an eye on her. Since then, she has cried every night, at 10:30 and going in starts and stops every few hours until 6:00 or so. When we come out to check on her, she always has her favorite soft toy in her mouth and is pacing as much as she can in her kennel. When we let her out, she circles the coffee table, and will not drop her toy. I tried to take it from her tonight, and she picked it back up and resumed pacing.I was out of town last night, but my brother says she pooped in her kennel at some point, and her whining stressed out my older dog so much that she started crying too. I don't know what is stressing her out so much, and I don't know what brought on this sudden increase in anxiety. It's keeping all of us awake and frankly worrying me.Putting her out doesn't help and she is behaving normally during the day (following her regular bathroom schedule, eating and drinking normally, sleeping a normal amount.) She could stand more exercise, but we haven't changed her pattern at all. My other dog seems fine, and I trust that the older one would bark if there was any actual danger.Should I take my dog to the vet? Do I have to kennel train her again from square one? Is there any way to find out what's upsetting her so much? via /r/dogs http://ift.tt/2qznGNF