Breastfeeding and weight loss

Hi all! I’m 5’10” and currently 235lbs. I just had my second child. Prior to my first child I was 175lbs. A little heavier than I was used too, but a great weight for me. I’m looking to get back to the ballpark of 180lbs. I am currently breastfeeding though and am struggling with diet. Has anyone lost a good amount of weight while breastfeeding? I don’t want to impact my supply at all. Also, I am starting to try to work out more but can’t do any lifting due to an umbilical hernia. Has anyone felt really deconditioned when starting to work out again? I was very fit before my children, but now if I walk to fast I’m out of breath and my heart is beating hard. Thank you for any tips! I am desperate to get back to where I was weight wise.