You are not unphotogenic. Two things are going on: you have memorised a flipped version of your own face, and the camera was probably too close. Both are fixable.
Technique.
Light, framing, lenses and the small photographic decisions that separate a snapshot from a portrait.
Most advice here is taste dressed up as rules. Only two things reliably decide whether clothing helps or hurts: whether it separates you from the background, and whether it competes with your face.
Usually yes, and the reason has nothing to do with looking friendly. A held smile is what goes wrong, not smiling itself. Here is how to get one that looks like you.
A window on an overcast day is a large, soft, free light source. Here is where to stand relative to it, and the two ways people get it wrong.
Grey, white, blue, black or the room you are standing in. The choice is mostly about how much separation you need and how formal the destination is.
If you wear glasses every day, keep them on. The photo has to look like you. Reflections are the real problem and they are solved by moving, not by editing.