We recently adopted a 2 year old Rottie named Gabby. She was a rescue, so we are not certain of her past. I have worked on getting her on a routine to reinforce housetraining and over a week's time, she was doing really well. Last week, my sister was in town to stay with us. Her initial meeting did not go well. Gabby was showing signs of fear by barking at her and raising her fur on her back. She eventually calmed down, and was okay with her in the house. Initially, she followed her everywhere. As the days progressed, her behavior changed. One day, she pooped in the house. I immediately took her outside to finish. We do not have a fenced yard, so I take her on leash to do her business. She would not go and after some time, she stared to pull and tug on the leash. When I would try to get her to stop, she would get more aggressive with the pulling. If I tried to walk away, she would nip and my legs and arms. She only does this if we go in the back yard. If I let her out the front door, she is fine. She will give me her signal to go out. I let her out back to see if she would go. Immediately, she started to pull on the leash. I brought her back in the house and let her out the front door. She went potty. I walk her every morning and she is great on the leash. She heels, sits when I stop, etc. She started to mark in the house, even though we had recently let her outside. As soon as we would go upstairs for bed, she would open a back bedroom door and pee. . 3 days after my sister arrived, she would not stay downstairs in her normal place to sleep. We do not allow her upstairs and have a baby gate to keep her from coming up. She knocked the gate down and came upstairs. I brought her back down and she would whine and try to get the gate down. If I tried to correct her, she would jump at me and nip and my pants and sleeves. We have had her sleeping outside of her crate at night for 3 weeks without any of these issues. Since this started, she has now started to nip and tug at my pants and sleeves in the house. I tried to put her in an alpha hold, however, it only escalates her behavior. If I give her a correction, she gets a "look" in her eyes and starts the nipping. My interpretation, which could be totally wrong is that she is challenging me and it is getting worse. My sister is gone and her behavior is better, but she will have an occasional nipping session. I tried to distract her with a toy, and it seemed to have helped.
Is she bored and looking to us to play? Does she now think she is the alpha? I am torn because I follow most of the alpha training. She sits and waits for us to go through the door first, we do not greet her first in the house, etc. We do obedience training with her every day and she does great. Could it be a trust issue?
I need some help, please.