Hi,
I guess you have generated gerber for only bottom layer.
While generating gerber select layer tab thier select the layers which & all you want to be included in gerber or simply select used ON by clicking on plot layers.
You will have supplies going to the chips and a 0V (GND) signal, these tracks are the same width as the signal tracks, it is better to make them larger.
Also as I said earlier you change layers in some places where there is no need to.