There appears to be something wrong with my red tail boa. Help?

I've only had her for nearly two weeks. Recently, she hasn't been as active as she usually is, and she seems weaker and doesn't cling AS tightly as she usually does when being held. Now, she is about to shed, and I know that their behavior changes a little during this time period. Anyway, I've noticed that, since she entered her blue phase, the skin around her neck has been really loose. Also, there's always saliva coming from her mouth, but she doesn't wheeze. I assume that she's dehydrated and has a respiratory infection, but I'm not entirely sure. When we had ball pythons, I recall the skin around their necks appearing loose right before they shed. Is that normal? Also, is it normal for her to become less active before she sheds, and weaker? Also, how long does it take for her to start shedding after she goes into the blue phase? Her eyes had been clouded over, and now they've returned to normal. How much longer should it be before she sheds, assuming she isn't stressed or anything? I've been trying to keep the humidity up in her tank, as well as giving her soaks in room temperature water daily. I realize there's a lot of information here, but I'm just trying to make sure she's alright, and I don't want her to suffer due to my incompetence. If I've left out any information that could be helpful, please tell me. Is most of what's going on simply due to her shedding, except for the excess of saliva around her mouth? Some of it may actually be nothing, but I have a tendency to worry about her. Any help that can be given would be much appreciated.