I believe I did check to see if it was advancing, yes
Well, if you opened the back with the film mid-roll then that is the cause.
Film is light sensitive. It must always be kept in total darkness except for the actual intended exposure for the photo you intend to take. Opening the back with the film mid-roll exposes the film to light and ruins it (or at least a part of the roll).
To check if the film is advancing on your camera you only need look to see if the rewind knob turns when you advance the film. If it turns as you move the lever then the film is advancing.