goredgo- Day 7 how to engage a non- exisitent core?

I will be the first to admit I was lazy today...

Joe (my son) got a bad ear infection last night and had a fever of 104 so we ended up in the ER for about two hours in the middle of the night. When we got home he was hungry so by the time I got back to bed it was after 3 a.m. The baby slept in a bit but was still up at 6 a.m. Even though I woke up with a cough (thanks Fairview hospital!) I decided to push through and do the Power Cardio workout.

I started off ok. Last week I focused on learning the moves and pushing through to the end of the workouts even when I was tired. This week I really tried to listen to Shawn T and make sure I was engaging my core, getting my knees up, etc. My problem is I have a non-existent core. Even when I try to engage it I don't feel much. This is one of my favorite workouts so I wanted to try and push through to the end but my body gave up on me with about 6 minutes left in the workout portion. Even my sons cheering me on didn't help (Joe kept asking me why I was stopping and every time we did power jumps Paulie would bounce up and down in his excersaucer.) I skipped to the stretching. Even with skipping the last 6 minutes I was very sweaty and exhausted.

I have my curves day tomorrow. I start Curves smart which will track my progress and give me daily updates at the end of my workout. Hopefully I will see some progress. I know my body is changing on the inside but I am more than ready to see results on the outside.