The recommendations I've seen regarding exercise all indicate that it's a good idea to at least cut your routine in half for the first three weeks or so, to give your body a chance to adjust to the plan. You may want to try doing half the reps, or using minimum weight, and see if that helps. If you're drinking the 55 shakes (the women's pack), you might want to think about bumping up to the 70 shakes (the men's pack); they have a little more protien and a few more calories, and are recommended for very active women.
Be careful with the strength training. If your body doesn't get enough calories during the day, it will go into starvation mode and hang on to as much poundage as it can. There are some people on this forum who've even mentioned that they can't exercise much at all, or their weightloss stops. You could try reducing your workout, and see if that impacts your rate of loss. If not, then we look elsewhere to see what the cause is.
Good luck - keep us posted!
- Dayna
PS Oh, and as Lisa mentioned, that 3-a-day shake protocol is old; you may now mix and match supplements (except bars, of course) at will. Hurrah for pudding for breakfast!!