On high alert

[puppychaos]

In the last couple of weeks or so, my 7 month old puppy has went from being pretty chilled out to barking at the door and barking at any movement outside when she's in the garden. She even barked at someone when on a walk last night! Also, she's been a bit rough with her dog pal when she was out with her dog walker - this has happened twice on both Thursday and Friday. She's also getting more aggressive towards us.

This is really sudden and there hasn't really been a build up, especially the barking at the door - she started doing it one day and hasn't stopped. Is there anything we can do to calm her down? She's really out of sorts.

I should say that she's a rescue pup and we've had her for three months now.

Secondary fear period, perhaps - I htink that's about 7-8 months? In which case, it should pass, given reassurance.

dogcommunication.co.uk/suddenly-spooked-secondary-fear-phase-in-adolescent-dogs/

7 months is the start of the teenage phase. They forget any training and think they can do what they like. You have to go back and reaffirm the training.
Distraction is key for barking at people outside. If you see someone nearby get her to focus on you or a treat in your hand until they've gone past. You can give her tiny bits whilst walking along, as long as she isn't barking and is looking at you.
As for the door barking, mine did that and I never got her to stop. Sorry. But, you can solve it if you teach yours to bark and then you teach them not to. Sounds odd and the wrong way round, but people have had success with it.
Just read she's border collie x. I've heard they can be fixated with things. My friends was fixated with cars and would try and run after them as the drive past. You do really need to work at distraction techniques so as soon as you see her try and scratch at your door, you distract her with a toy, or a high value treat.
Does she play any mentally stimulating games when at home? They are very intelligent so need not just physical exercise but mental exercise too.
I hope you find a way through. This stage is short lived, but feels so frustrating as it makes you feel all your hard work was for nothing.