Maltese Injury?

My 5 month old Maltese had a bizarre health issue this evening. She was
energetic and full of energy. She jumped off of a step and landed hard.
I called her over to me so I could love her and give her lots of rubs
to make it better. While I was playing with her she began shaking. More
like shivering like she was cold. I looked at her and she looked fine.
I put her down on the ground and she was disoriented and could not
stand. She fell over. I thought maybe she had injured her leg and
picked her up again. She stopped shaking quickly after and when I put
her down again she was completely fine and energetic again. The whole
episode lasted no more than 2 minutes.

Any ideas?

Shaking and shivering are common to most toy breeds, most of the time
the shaking and shivering are triggered by sometimes being scared,
cold, etc. I had a Miniature Pinscher who did the same thing most of
the day. I had that looked into and the vet said it can also be a
nervous thing. Larger breeds rarely shake like that, I am used to
having giant breeds and don't see it as often, but when I had a toy
dog, I became accustomed to it. A vet check would not hurt, I am sure
your vet will tell you, the common basics cold, scared, nervous. I
don't know what to tell you about the falling over issue, but I do know
that young puppies when playing too much can get a little dizzy, I have
seen it alot, especially with pups under 8 months. I am no vet by any
means but have been around dogs for a long time and have seen so many
health conditions especially with my large breeds as well as have
friends who show and breed small dogs, as I said if it really concerns
you, it would not hurt to give your vet a call. Good Luck!