Anyone good with animals?

My dog is upset over something, for the last few days she's been whimpering and almost crying while walking around the house. Nothing traumatic has happened lately(or ever for that matter) but whenever someone leaves the house or returns to the house she just gets upset and whimpers for a while, even if she's sitting beside them! She has a little squeaky welly toy that she wont leave anywhere, she won't take it out of her mouth unless to eat food or go for a walk and this is not like her at all! I'm worried about her, it looks like she's having anxiety attacks, she has very strange looking dreams, she figgits a lot more than usual.

Does anyone know what could be wrong with her or whats upsetting her?