Ddog2 has been with us since last Sunday. She was anxious at first but has really settled into the home, although still exhibits fear and anxiety out of the house with things she's not used to - people, cars, other dogs etc.
However since the third day she has been with us she has randomly snapped and growled at us. The first time it happened she was curled up asleep next to DP and he absent-mindedly stroked her and she growled and snapped at his hand. Since then she has done it several times a day/evening but when she's been awake too. It's often when shes sat with us on the sofa and receiving cuddles (which she has instigated) or after she's approached us, so it's not like we're forcing ourselves on her. I'm very good at reading doggy body language but this is just coming from nowhere, when she's otherwise giving off relaxed signals.
As an extra - this afternoon she also actually growled and bit my leg when I was leaving the house (pulling her inside by her collar as I have done several times a day for the last week!)
What could be behind this? She's had a clean bill of health from the vet. How should we be dealing with it when she growls/snaps? Should we remove sofa privileges? She's has a bad start to life and shows signs of having been hit/punished with strong voices (we've realised this in the course of the past week) so is it just she's still on her guard and not used to relaxing or...? Help please!