Week 3 FB Burn: What's wrong?

Hi..I'm enjoying FB Burn so much. Weeks 1 and 2 were challenging, but I kept up. This is my first workout program that includes strength training. I've made it to week 3 and every workout has been a struggle. I'm easily winded, my legs are burning, and I'm just awkward! What could be wrong? Is it something I'm doing? I had a hard and emotional last weekend. Could it be affecting my workouts?

Thank you in advance