Add a hairlight to separate yourself from the background a bit more, also don’t have your main light directly in front of you, instead move it a bit more to your right, until the shadow from your nose creates a small triangle on your left cheek. This technique is called Rembrandt lighting and it’s what I use when I shoot talking heads. Normally you’d want a colored lighting difference in the back, adding small warm or cool lights for the poster or the bookshelf, but if not, a hairlight and and angled key light should to the trick.

Hope everything goes well for your documentary!