first off, Congratulations! I would go into a different website to determine your RDI try https://caloriecount.about.com/register,
I found it to be a better # for my height and weight.
Then I would look at the foods you're eating to attain that calorie # per day. It should be good healthy food choices especially while you're nursing. Good wholesome veggies , a little fruit, clean proteins and good fats like avocados.
Eliminate or cut down on the processed foods, packaged foods and 'treats'.. While you're trying to lose, these may seem like 'treats' but they have no nutritional value and avoiding sugar is the best thing you can do for you and your baby.
If it is a plant, eat it, if it comes from a plant, don't!