Wouldnt the light rays look weird without the source of them ?
Everybody says something different... i am confused about what to do

But it keeps me motivated to keep taking pictures
This picture, along with the varied comments, is a perfect example of recent discussions about "vision." If you're confused about what to do with it, perhaps it's because you don't *really* know what your VISION for this piece is. What are you trying to convey here? What do you want people to see, or feel, or experience, when they look at this?
THAT will give you a better idea of how to process it, whether or not to crop it, etc.
For me, the processing, and the title, makes it seem that what you're going for is a dark, foreboding feeling, a sense perhaps of impending doom. If that's the case, I'd definitely lose the sun at the top, because it serves to brighten the whole image--for me, anyway, it changes this from a sense of impending doom to almost one of hope, seeing that the sun might just break through and eradicate the coming storm.
I do agree with Mish that the cloud on the upper right is distracting, it's WAY over-processed, imo. I'd tone that down, or crop most of it out (which would happen anyway, if you crop out the sun).
The building, for me, actually ADDS to the story, but that small bit of white right next to the track in the distance is distracting, and again detracts from the overall "dark, gloom" atmosphere of the picture. I'd either clone it out or burn it so it's darker like the other building.
You say you don't know how to clone in gimp. What better time to learn than when you have piece that you can do it on? Google "how to clone in gimp" and you'll get plenty of tutorials you can try!