It sounds like it is too early to determine your damages. If the overdosage does cause you kidney failure then you definitely need to pursue. Do not call CVS anymore. Contact a local malpractice attorney to discuss. They can tell you what the statute of limitations is. The case would have to be brought in AZ if that is where it happened. Hopefully your kidneys can handle the extra dosage since you only took it for a week.
I agree, do not call CVS back. Keep the prescription bottle and contact a local Phoenix-area personal injury attorney ASAP to for guidance on how to proceed. It could be too early to determine what your damages are, so continue to treat with a doctor so that your problems are documented.
DISCLAIMER: David J. McCormick is licensed to practice law in the State of Wisconsin and this answer is being provided for informational purposes only because the laws of your jurisdiction may differ. This answer based on general legal principles and is not intended for the purpose of providing specific legal advice or opinions. Under no circumstances does this answer constitute the establishment of an attorney-client relationship.
The statute of limitations will probably run two years after your discovery of the error. So you have some time to determine what injuries, if any, you have suffered -- which will be an important factor in determining whether this is something that you wish to pursue.
As usual, I agree with Mr. Curtin, but it would probably make some sense to contact a lawyer who can more fully explain what to expect going forward if you have questions at this time.
Your claim is probably governed by one or more limitations periods. This means that you must take certain actions within a certain period of time to preserve all of your rights. A limitations period can be very short. I encourage you to speak with a lawyer who handles medical negligence cases in your area as soon as possible. I would be happy to help you find someone.