Rescue dogs need time to acclimate to their new homes before their "real" personality shines through. I'd suggest stopping the outtings with this pup for about 2 weeks. Let her get comfortable in your home, with you, and her routine before bringing her out again.
It may not seem like it, but this poor dog is scared and probably just acting out of confusion and a need to react to a situation in order for her to try to control it (herding breeds tend to do that genrally anyway).
So, after a few weeks, see what a wonderful pet you have. Slowly start taking her out and see how she reacts then. IF this is a real problem, you can adress it then. If it isn't, good.
Also, in my humble opinion going to positive reinforcement obedience class is critical to developing a strong relationship with a pet- especially a rescue. Many are not that expensive ($10 for a one hour class) and are tons of fun. You don t'need a behaviorist or specialist at this point, just go to a class and develop a communication system with your pup.
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Chelle and the rest of the crew including, but not limited to Kita and Taiko (the shiba inu wrestle maniacs), Adi (reserved and dignified tabby cat), and all 28 reptiles