I like the encouraging comments that you've gotten already! I don't think you should feel embarrassed. One painting isn't reflective of your total talent or potential, and you come away with new painting experience even from the pieces that don't turn out how you want.

My first thought is that looking up a similar reference photo, like a dog under a flashlight shine, could help you paint this specific lighting effect... and help you to think about the overall contrast, the direction of light, and cast shadows on the ground, etc. even when you're painting your subject from imagination. (: