I agree with all of the above. Please see and opthamologist tomorrow. Anything like flashes could be serious. But it also could turn out to be fine.
I was gardening a couple of years ago and when I stood up I had a flurry of floaters that were never there before. I called my opthamologist and they wanted me in the office immediately. They checked for a detached retina and other things. That's serious. Thankfully, the retina was fine but you sure don't want to take chances, Nana.
Sherrine