Your question doesn't give us a lot to go on without an example image.
In addition to the other answers regarding battery life, it may be that your camera has a small light leak that, over time, causes the film inside to be overexposed.
If you use a fresh roll of film, shoot it fairly quickly, and then remove it from the camera shortly after you exposed it you can compare those results to the film that was inside the camera for an extended period of time. If you have a light leak it will only show in certain areas ifof the film that will give you clues as to where the camera is letting the light in. If the results are the same as before then you know there is something else going on, most likely with the light meter. You can test that by shooting part of the test roll manually in known light with settings known to be correct for that light (i.e. f/16 at 1/100 second with ISO 100 film when in bright sunlight).