I had one a few years ago and I freaked out, too. Even called my doctor. She explained what it was and also said, that only if you get flashes of light, there's reason to worry.

At first I thought my glasses were dirty, but no. So I got an appointment with an eye doctor and he found out that I have the beginning of a cataract in one eye, too.

Getting old sucks, but I suppose it's better than the alternative.