Representatives, at least the ones in the House have districts. Whatever district you live in that is your representative. Senators represent the entire state not just whatever little funny shaped notch Congress has drawn out on their political Etch-a-Sketch. If your interests correspond with the state's interests then your Senators may be representatives but if they differ, say you own a rural farm in a primarily industrialized urban state for example then your senators may not be representing you at all.

The above was in response to have2cit's post.