Not sure where else to turn except maybe other chi parents. Doggy depression? Desperate long post.

I will try to break everything down so that major points are clear. Please bear with me.

Hello all. I am the loving daddy of a 6-ish year old shorthair fawn chihuahua named Nomi. We raised her from a tiny puppy with lots of love and socializing, play and snuggles from as many people as possible. She was the type that always wanted love and food from everyone as long as she could sniff you out for a minute.

Side note: She had not been spayed. Yes, I know it's irresponsible. Yes, I will get it done asap. I'm not sure if it's a possible cause. Please just continue.

In the house, there have been 5 people. Me, my gf, my mother, my father, and my brother. Also for the last year or 2, we have had another chi, a boston terrier, and a few assorted cats. Normally, Nomi has always been completely fine with everyone, snuggles with cats and dogs alike, and has just been the absolute queen of love in the house. Also, my father was very lenient with her diet, feeding her lots of people food over the years with seemingly little to no problem. She would also spend a lot of time with my father, as he worked from home, and loved her to death.

Though, back in December, my father passed away from a heart attack (Thanks in advance for any side condolences). In December she was fine. But, last month, she started some heavy nesting behavior that we initially thought to be a false pregnancy. We decided to wait for a few weeks, as we were extremely busy in the middle of preparation for buying our first house.

Though, in the last few weeks, her behavior has gotten different and worse. She doesn't want to play at all whatsoever. She's not eating nearly anything. She's yelping at most movement or contact, despite having no reaction to pressure test by myself or a vet. She seems to just be a little loaf of sensitivity and sadness.

Yesterday, I took her to the vet and had about $700 worth of tests done on her, including blood work and others. The vet and I had a fairly long discussion about it, as almost nothing came back wrong. IIRC, she had a mild fever that broke as soon as they introduced some water into her system for one of the tests. I checked her temperature last night before bed, and she was still at the low end of normal range.

The next step from the vet was what she referred to as a "fever of unknown origin" test, or another more extensive blood screening panel they referred to as a JAR test, "Just Ain't Right". As money was starting to become an issue, I told her I'd go with the appetite stimulant and pain meds she recommended, and see where that went.

That vet visit was yesterday, and I've only seen her eat like normal once, which was an hour or so after we got home, as the vet had started her with an injection of the appetite stim. Since then, I haven't seen her eat, and I wasn't able to watch her in the backyard due to cold windy nighttime when she last went out.

She has been reclusive and lethargic. No play, minimal snuggles, and sensitive to everything. She will yelp even if you just look like you will touch her. Not like her at all since the day we got her.

I've been scouring Google for ideas, and it seems like absolutely everything could be a possibility according to her major symptoms. The only next step I could think of is that, in a previous vet visit, she was diagnosed with a fatty tissue deposit around her left hip. It was never a problem, and the vets said it was completely benign. Though, now I'm wondering if it's doing anything to her spine, necessitating a neurologist visit.

I'm almost totally lost.

So, in summary (kinda long TL;DR):

• Female Fawn chi, somewhat recent shots, not fixed
• Lives with me, gf, bro, mom, dad, 2 other small female dogs, and assorted cats. Super attached to me, gf, and dad
• Dad died in December
• Her mommy and I have recently been packing for buying our first house
• Signs of nesting starting last month
• Nesting changed into complete lethargy and apathy, including loss of appetite and major increased sensitivity
• Vet visit including blood work, urine analysis, x-rays, and physical exam show nothing unusual. Zero answers.
• Could send for extended blood and urine tests, potentially leading up to a neurologist visit.
• Could also be depression

Am I just going crazy?!? Please, other chi mommies and daddies. I just want my fat happy love-loaf back =(