Hey everyone, thanks for the replies.
I checked my shutter curtains with a strong light in a pitch black environment and couldn't see any holes in the shutter. What I did notice was that light seemed to be coming in around the top and bottom of the shutter curtains, but was more of a line of light along the edge of the curtain. Could this be a possible cause of the dark spot on the negatives? I've used this particular camera for about 4 years now and this just almost all of a sudden started happening a few months ago. I'm very careful to never point my camera at the sun or leave the lens wide open when walking about outside.