^This. I have to admit when I meet a Mini Aussie I expect them to be emotionally/mentally unstable. That being said, it's possible this dog just needs a lot more exercise and mental stimulation. Get some toys like kongs or dog puzzles, and work on training.I also find the Mini's seem to be a bit more neurotic than the standards. I've only met one Mini who wasn't off the walls crazy.
No dogs understand the word "no" unless you demonstrate what it means. My dog Stella does have a quiet command, but I had to give the hand signal and verbal repeatedly with treats before she understood what it meant. Also, don't use the word "no" for multiple things. If you want to use no for a general "stop doing that!" the dog will get confused. The pup might be able to understand if "no" means "stop barking" but if it also means "stop chewing the furniture" "stop jumping on the counter" and "stop running out the door" then your dog will likely not listen to anything. Use separate commands for what you want the dog to do/not do. If you're not experienced with training I'd recommend a class.