This reads really familiar to me from about a year and a half ago, going out with my new iPod and being really distressed at how difficult the supposedly "easy" first week was. I didn't have the knee problem but I had serious trouble breathing through it.

I agree with Temve though, it really helps to keep the jogging slow. And remember that you can stick with the same level for a couple weeks until it gets more manageable. But with practice it really does get easier!