It's good that you took Nina quickly to see the vet. But it's odd that he hasn't been able to offer any solution, or even explain anything to you...? Basically it appears he just left you with an "I don't know" answer.
I haven't had personal experience with a dog who had seizures, but have heard that a seizure can cause some abnormalities in behaviour and function for a little while afterwards. Also they are very exhausting, so Nina might just feel a bit wiped out as well
It's "cluster seizures" you want to avoid, if possible, as too many back-to-back have been known to cause some brain damage sometimes.
I would suggest that you either speak again to your vet about what is the way forward.....or if you don't get satisfactory answers, then take Nina as soon as you can, to another vet for a second opinion.
There obviously was a cause of her seizure and it would be good if that can be found, and any medication she needs to be given to hopefully prevent any more.
I hope she will be feeling a bit better soon and be able to get up, poor girl. That must be so hard for her.