When you mentioned that she looks around like she's chasing a fly......my first thought was floaters or cataracts. I actually have cataracts, and, while they don't bother me too much, when there is really bright light - like being outside on a snowy day, or at night when I am in a well-lit, lighter coloured room, I see the floaters. AND......I can not count how many times a cataract has caught my attention and I swat the air because I think it's a fly or a bug!!! Of course, I'm intelligent and it only takes me a minute to realize it's just my cataract but a dog wouldn't understand that and keep looking for the "fly".
I also know that when my Bella started going blind she would sit and just weirdly look around - like she was "off". Now, of course, I know that she couldn't see well and was also likely trying to figure out what was blocking her vision.
It wouldn't surprise me if it's Gidget's eyes that are the problem.
I hope Gidget is okay. Let us know how she does.