How can you say it did nothing: you said it yourself - you started it last week.
OP: Understand that you need to know what you are doing, and you need to effectively utilize the benefits of a product, to see whether it works or not. Chemically, every supplement should do exactly what it is supposed to do. The person taking the product, their body's biological reactions to the chemical reactions, and the workout program, intensity, frequency, and effectiveness, are only a few of the numerous factors of which determine if and how well a product will "work."
It can bother your stomach as well. If you feel nautious, this is usually a normal reaction to extremely potent creatine (and sugar and carbohydrate - look at the back of the label) such as Cell-Tech and Superpump250. In this case however, I have found that it is usually skinny guys who get this reaction, because it is just simply too much for the body to be able to take -- and the queasy stomach is a sign of that! Simply lower the dose below the recommended amount until when you take the supplement, it no longer bothers your stomach.
Let me know if this helps. I have a lot of experience with this kind of thing.