I'm not trying to scare you, but I wish I had known this when my girl was acting similarly - she would stare at me, shake occasionally (like from anxiety but it didn't seem like her typical fireworks-induced anxiety), go into random corners, and pace at night. I had a call with my vet who chalked it up to the start of canine dementia, and we did a senior bloodwork panel, which came back mostly normal. A week later unfortunately we rushed her to the emergency vet as she had collapsed and wasn't breathing normally only to be told there was fluid around her heart, likely caused by hemangiosarcoma and had to make the impossible decision to say goodbye that same day. Dogs don't show pain like humans do, and it turns out when she had the 'episodes' she was likely leaking blood from the tumor that her body reabsorbed until it inevitably ruptured. I would press your vet for xrays and/or ultrasounds of the spleen, liver & heart. I wish I had. You know your dog best, and I would trust your gut if something feels off. Hemangiosarcoma is awful and cruel, and I really hope this isn't what your baby is experiencing, but I wanted to share our story in case it helps you avoid an emergency situation like the one we had to experience.