A sprained ankle can take quite a while to heal, and if it has been only one week I would definitely give it more time. A sprained ankles, as you probably know, occurs when the ligaments surrounding the ankle become stretched too much by twisting, falling, and the like. This leads to weakness, swelling, and pain. Because the ligaments do not have much blood supply, it takes them a while to heal. Often, in fact, it can be weeks to months before a sprained ankles is totally back to normal (obviously this depends on the severity of the sprain).
I highly recommend that you follow up closely with your primary care doctor
about this issue. As long as the pain and swelling continues to improve, you should rest assured that eventually this will heal up. You should continue to rest, to elevate the swollen ankle, and to avoid vigorous physical activity until the swelling and pain is totally gone. The main mistake you can make is going out and trying to exercise too soon, as this just risks reinjuring the ankle.
Your primary care doctor will be able to help you decide when it is safe to begin to resume exercise.