I can totally understand how you are feeling. My last dog was a cattle dog, and I didn't have a yard for her. That meant that unless I could get her to the park two or three times a day, and at least one of them a nice long run, she was completely crazy. She was mouthy as a pup, constantly biting my kids and me, jumping, barking, into everything, you name it. She was the hardest dog I have ever owned.
Now I have Bella who is 5 months old, and I thought she would be a breeze compared to Pepper the Crazy Cattle Dog. Somethings are definitely easier, but Bella is harder in ways that Pepper wasn't. She doesn't catch on to things as quickly, she has resource guarding issues, she's very submissive so requires a lot of leaderhsip to feel secure, etc. She isn't any better or worse than Pepper was, just different. AND, even with Bella there are days that I just want to scream! When things get tough for me, I put Bella in her crate with a chew and I go upstairs for a bit. Sometimes all you need is a break. Be diligent and don't give up. Your hard work will pay off in the end.
I agree with others that there is the posibility that Naiya isn't the dog for you. Pepper wasn't the dog for me. After two years, I realized that Pepper had too much herding instinct in her and really needed a job, a yard and something to herd. She was not meant to be crated and in the house. I loved her so much and it was the hardest thing I ever had to do, but now she works on a cattle ranch in Wyoming and I think that is the best thing I could have done for her. I didn't come to this decision lightly though. I met with a behaviorist, went through lots of trials and months of different treatments before she (the behaviorist) and I agreed that Pepper was not a good fit for my life. Don't do it until you're sure, and wait until you get past the puppy craziness because ALL puppies will test you, and push you to insanity sometimes!
Good luck, sorry this is so long. Please let us know what we can do to help you and Naiya.
Angeleen