This is what is known as continuity and on professional films, there is generally one or more people whose sole job is to document and check continuity of shots. (The continuity or script supervisor.)
The first thing to know is that as long as you are close, most people aren't going to notice very subtle differences in position as long as you shoot one scene at a time and don't try revisiting the same scene from the same angle.
If you do need to re-shoot a portion of a scene, use similar lighting and subject positioning, but change the camera angle intentionally. When you cut between them, it will feel like simply adjusting to a second camera and nobody will notice minor changes in lighting due to the difference in angle. If you try getting the exact same camera angle and fail, then that will be more noticeable.
As for keeping positioning of lights and subject roughly consistent, take photos of the setup, mark light and subject positions with masking tape if you can. Take measurements of lighting height. Possibly place marks on the center target locations for the lights as well if possible. This gives you position and direction of the lights.
The photos give you an idea how modifiers were configured. Referencing other footage from the previous shoot and/or photos of you while filming will give you details about clothing, hair style, body position, etc to make sure that it appears to be one continuous shoot rather than two separate ones.
You may also want to consider blocking windows or shooting on days with similar weather conditions at roughly the same time to ensure similar external lighting conditions as well if that is a factor.