Actually, it does infact portray solitude quite well. Take into consideration that most lighthouses are on either penisulas or on islands totally seperated from humanity. Also take into consideration that most lighthouse keepers are infact in solitude living by themselves. You need to be more constructive with your criticism. Comments like that just make you look like a jerk.
Your attempt was very well founded. My only suggestion would be to use less darker hues in an image like this. It appears grungy and thus it takes away from the emotional impact you were meaning to obtain.