If the negatives are overlapped like the prints, then you've probably got a camera problem. It may be something simple, such as not getting the film loaded quite right as Woof suggested. Sometimes you can tear out sprocket holes and that might cause the film to advance wrong. But it could just as easily be the lab. I turned in a roll of Kodachrome to be processed at my camera store the other day and the girl at the counter had it run through the E-6 processor because she didn't know any better.
Luckily, it wasn't anything important.