Puppy troubles with our 5 month old

Hi everyone, I’m looking for some honest, experience-based advice about our puppy.

We have a 5-month-old Australian Shepherd who has been with us for about 3 months. From the start, things have been very challenging. She is extremely sensitive, gets overstimulated very quickly, and struggles a lot with self-regulation. Calm moments do happen, but they’re short and inconsistent.

She has had repeated Giardia infections and digestive issues, and is currently teething, which I know can affect behavior. We’ve tried to reduce stimulation as much as possible (lots of rest, quiet environment, very limited activities). Interestingly, she often settles best when she is in a low-stimulus space away from us. When she’s close to us, she frequently becomes over-aroused, vocal, restless, and unable to settle.

We’re trying management over “training” right now, but it’s hard to know what’s realistic to expect. We don’t need a perfect dog — just something that feels manageable and stable enough day to day.

I’d really appreciate thoughts on: • Have you had a very sensitive, easily overstimulated puppy that improved significantly with maturity? • Does this sound like a normal but difficult developmental phase, or something more concerning? • What would you focus on right now: rest, structure, professional help, or something else?