
This is called seperation anxiety, and is not uncommon in rescue dogs. Your slipping out actually probably didn't do her any favours. As far as she was concerned you had simply disapeared.
She needs to learn to cope alone and to trust you will return. This is done slowly by leaving her for short periods of time when you are at home. Baby gates can be used so that she can see you but not be with you all the time. It is a bad habit to allow her to dog your steps constantly. Stat with times when she is already sleepy or relaxed, say in ehr basket, and leave the room briefly, not long enough for her to start a fuss. Return but do not fuss, her. after a few seconds if she remains on her bed relaxed, just a short word of praise.
The idea is to work up the time and keep leaving and especially returning low key.
If she is ecstatic on your return wait to greet her until she has calmed down. Ignore her overtures until she has calmed, the greet her gently but without too mcuh emotion.
The idea is that there should not be a huge difference for her whether you are there or not. that way she will cope on her own with a Chew, bone, toy etc and youyr leaving and returning are no big deal.
The idea should be to never make the distredded behaviour rewarding by consoling her, and never return to the room until she is quiet.