Dog panting and shaking

[amlsunshine]

Hi all I'm new here. I have a question. I have a Shiba Inu who just turned 3 in June. When she gets scared she will shake and pant. Things like loud noises scare her, as I'm sure they do most dogs. However the past few nights she has begun disappearing at about the same time each night. We'll find her down in the laundry room or under a bed and she will be shaking and panting like she's scared, but nothing will have happened. She will also want to be held once you find her and will climb in my lap. Anyone have any idea what this is? I know that I should call the Veterinarian but they have been closed b/c of 4th of July. I have a baby on the way and cannot afford to take her to the emergency Veterinarian unless I think it's necessary, which right now I don't. Tonight she started shaking a little and I hurried and gave her a Benadryl, which seems to have helped so far. Thanks in advance!