Congrats on your third child!! It's really REALLY impressive that you picked up Insanity just 4 weeks after giving birth!
I think your goal should be to hit that 2,000 calorie count everyday because 1) it'll give you fuel for the workouts 2) it'll help you blast fat faster because your body won't feel like it's starving and needing to hold onto its weight. Does that make sense?
With that said, you are doing GREAT! Remember, it took 9 months to put the weight on it may take just as long to get it off and get to your goal....but it is worth every second. 5 inches is HUGE! I agree--month 2 is insanely (no pun intended) hard. As long as you are pushing yourself to failure you are going to see great results...even if you are having to pause or skip a couple of reps because you HAVE to (not because you want to)
I think you are doing great! Do you have an accountability group or a group of friends that support you? I'm in a group on Facebook I started after not having a whole lot of positive, supportive friends of my weight loss. We share tips ,meal plans, questions, progress, etc. We also do a monthly challenge and giveaway....one of the girls just finished P90X and you should see her! After 3 c-sections she has abs like Pink! I think having the group helps keep me motivated, and it's also a great place to get help. Would you like me to add you? My profile is fb.com/kaleesorey if you want me to