Dog going nuts in home. Please help!

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I'm going to post this in several places because I'm not sure where a question such as this should go.
So, all of the sudden my dog is very anxious, whimpering and crying, wanting to be outside, scratching at the window, staying glued to me and my boyfriends sides except when she is at the door crying to get out, and really looses it when we have to leave for work leaving her at home alone. This has happened before and it seemed to have something to do with the fact that she got a spider bite that caused a reaction in her. After treatment with meds she got better. And it was only a day or two this. This time we cannot figure out what it is? I even considered carbon monoxide or something of that nature was in the house, but it tested fine. This as been going on for a few days now and is getting worse. She had us up all night. She is also jittery and very sensitive to sounds. Every little click or squeak from the heater vents makes her jump and/or get more anxious. She does have a vet appointment but I have a feeling that he wont find anything wrong.

Can anyone with intuitive or other abilities tell me what may be causing this?