Teething Turning Very Aggressive....?

I just got a 3 week old apoo, and she's teething like crazy. I bought her chew toys at Petsmart, and she loves them. The problem is that she only plays with them, but doesn't chew on them for her teeth that I see; Instead she comes and bites my fingers and feet [A LOT, especially with sandals] =( I've tried correcting the problem by giving her the toy, but she refuses. Not only that, but when I do play with her, by making her run, she attacks my feet and starts to bark hysterically. I go hard on her for this, although it makes me unhappy, but she doesn't get it. What can I do so that I can fix this problem as she is growing? The habit is getting her a little aggressive as I play with her. I don't want to turn her into a gnawing machine at such a young age. =(