dont know what is happening to my chihuahua...

Question
my dog is a year old and she is mix of chihuahua and something ( don't know
what, but size, shape resembles chihuahua a lot). her name is cocoa and she
is very much loved. she eats healthy and usually plays a lot. me and my
boyfriend own her for about ten months. she just had her first period about
three months ago, but she hasn't got operation.

last weekend, we went out and left her inside of house for 5-6 hours which
rarely happens to her.  when we came back home, she was a little bit strange.
happy to see us back but was shaking a little, and crying and whining so
much for the rest of the evening.
i noticed something else. when i woke up next morning, i found a couple of
toys in our bed. ( cocoa sleeps in our bed.) i've assumed that she took them
in midnight. next day, she slept all day on sofa with her stuffed animals.
didn't wanna play that much, and didn't eat that much. and that night, she
got up around 3 am, crying and whining, got out the bed and went to next
room, came back to bed with a stuffed animal. she would go back and forth
and gathered 6 of them and went back to sleep among them. she did the
same thing next night. during the day, she wouldn't wanna leave her stuffed
animals, and seem like she just wants to sleep. i try to take her out to field as
much as i can. a bit worried.. the weather has been chilly these past few days,
but would that be why she doesn't seem that lively?
is she depressed? what can i do to make her happy...?
please help!  

Answer
Dear Mozzi,
Thanks for the question and details. Is it possible that she has mated with a male and is carrying pups? She may be going through some hormonal changes.

Anytime there is a marked changed in behavior, it's best to rule out medical problems. I would have her thoroughly checked by your vet. Good Luck!