See if these blemishes are in the same place on each photo. If so, I'm pretty sure you have goobers on your sensor. There are posts on this forum about what to buy and how to remedy this. It's a little scary at first, but with the right tools and a little care, you should be as good as new.
I don't think this is a sensor failure. One would expect that sort of thing to be on a pixel by pixel basis, yet your photo shows distributed globs that affect numerous pixel sites in a symmetrical way.