I am sorry to hear about Megan.
My name is Rebecca. I am a veterinarian, and will do my best to help.
If you look at her eyes, do they twitch back and forth? It can be subtle, but if you look close, you might see this.
yes. right eye twitching
There is a condition we see in older dogs, that comes on suddenly. They circle or walk to one side, can't stand up without falling, and sometimes have a head tilt. These dogs will have nystagmus, rhythmic twitching of the eyes.
In many cases, this is a acute loss of balance, due to inflammation in the vestibular area of the brain.
It can be brought on by a stroke or a brain tumor, but more often we do not know the cause, and the dogs get better in a few days to a week or so.
It is called "idiopathic vestibular syndrome" or "old dog vestibular syndrome".
Meclizine, which is available here in the US over the counter, can be helpful.
Does she need emergency treatment tonight ? Is there any treatment?
You might want to have her examined to confirm this is what she has. If she does, there is no treatment ( except to try the meclizine) but time.
You could do an MRI brain scan to look for a cause. If there is a tumor or a blood clot, it would be seen on MRI. But, if it is idiopathic vestibular syndrome of older dogs, even a brain scan would look normal.
So you could just observe her at home, and give the meclizine. If it is what I suspect, she should show improvement in a day or two.
If she is not getting better in a day or so, I would definitely have her examined. Usually vestibular syndrome does show some improvement in a day or two. Usually when it first starts that is the worse they are, they do not get worse with time, but better.
Is there anything else I can answer, or help you with?
I am not seeing responses from you. I hope you can still see what I am writing.