Hello and welcome ... My name is XXXXX XXXXX I am an experienced small animal veterinary surgeon, I will be very pleased to work with you today and will try my best to answer your question to your satisfaction.
How long ago did this start?
about 2 weeks ago
Ok, one of the things that this could be and something I have often seen in older dogs is some form of congestive cardiac failure, in the early stages this can lead to small fainting fits such as you describe.
If this is the case prescription heart meds from your vet can often make a big difference ...
Another possibility would be some form of neurological disease, perhaps as a result of a minis stroke or even the start of a brain tumour but hopefully this is unlikely