30 Day Shred + another cardio workout in the same day?

risak

Does anyone compound the 30DS workouts with another type of workout on the same day? I do the workout and then walk my dog for about 30 at a fast pace, but I barely have anything left in the tank after Jillian has her way with me.

I just worry that 30DS along is not enough of a calorie burn?

I've just stepped up my exercise since May. From mainly dieting and just walking the dog to eating a bit more and exercising harder. I'm noticing more water retention and weight gain. I know muscle weighs more than fat but in 2 months could I be gaining muscle weight that fast?