i dont know how to see where the light comes from.
This highlights a fundamental problem. Before you try something as complex as a human face, you should learn the basics of how light works and how basic geometric forms are lit. practice drawing spheres, cylinders, and cubes in perspective and according to a distinct light source.
Right now you don't know how to think in 3d or know where shadows and highlights should fall, so what you have is a flat image made up of symbols rather than forms. You need to teach yourself to think about the form and planes of objects, and where light strikes those planes. There are exercises to cut down on symbol drawing, such as drawing an image upside down, but I'd also recommend you use photo references when you're working so that you can study how features actually look.
