Dreamer - Kelsey Dylan

I got to shoot with Kelsey Dylan last week, the first roll I developed showed that something is very wrong... very wrong indeed, and looks like somehow I terribly miss-exposed the entire roll, I shot 6 B&W rolls and 1 Color roll, I'm hoping that I simply changed a lens and this first test roll was the result of me not re-setting the aperture on the changed lens... if I miss-exposed the entire shoot I'll be very sad... Thankfully, we changed locations before I shot my 4x5's and all of those sheets so far have come out BEAUTIFULLY so FEW! Still, very nervous about the rest of these rolls... what did I do wrong?? I'm always so careful...