Its worth getting it checked out, mumsie - it can also be viterous jelly breaking away from the retina. I suffer from floaters, but a couple of years ago, I was out shopping, and a brownish cobweb type thing blocked my vision, it really freaked me out. I rang Moorfields in London and they said to come up the following day to A & E, which I did, and after many tests, they confirmed some viterous jelly had come away in a large lump from my retina.
This can sometimes tear the retina, but in my case, it hadn't. Yours does sound just like floaters, but I would get it checked out all the same.