4 weeks and fatigued!

I have been doing Insanity Max 30 and last weekend noticed I was a little dizzy and struggling to keep pace. A few days later, I received my BFP. While I have not been able to workout as hard this week, I am wondering what you all recommend? Stick with a strong cardio and weight routine and just modify as my body tells me? Back off Insanity and pick an easier program? Did you all notice an immediate decline in workout performace? Thanks for any advice!