Trying to find my new balance

I've lost 40 lbs. Started at 168 lbs and I did really well losing while eating 1400 calories. I am now 130 lbs and I have plateud for a month. I was hoping to lose another 5 lbs and I'm starting to gain it back even though my new calorie allotment is supposed to be 1600. I am also a breastfeeding mother. Do you have any advice for me?