Post partum weight loss struggle.

I gained 48 lbs during pregnancy. Started out at 165 and ended up at 213. I lost 30 lbs within 2 weeks but I can’t seem to loose the last 18. I am working out for 1 hour a day 6 days a week eating healthy and I can’t get rid of this last 18 lbs. I am 3 months post partum. Trying not to get discouraged but working so hard and seeing no progress is really taxing. I am drinking lots of water , eating high protein low carb diet and nota. Anyone have any tips or experience the same ?