3 months pp and very slow weight loss.

I still have 15 lbs to lose . I have been getting extremely fustrated bc I am only losing literally one pound a week , if that. I don't understand why bc with my first i breastfed and the weight just fell off . I'm breastfeeding again but this time I don't think it's helping with weight loss . Any thoughts, ideas, or advice greatly appreciated. Feeling very down!