First of all, mazel tov on the birth of your new baby, and have much nachas, always.
The biggest tip I can give you is to stop having agita over your present weight. You are nursing, and that will help you lose weight naturally, over time. Right now your focus has to be on the health of the baby and not on what you see in the mirror. Every one of the 50 lbs. you gained worked to give you a beautiful, healthy child, kinehora, and that is no small feat. Yasher koach.
Just eat and drink in a healthy way, don’t obsess over the weight, and go for long walks with the baby. You WILL lose the weight over time. You may never look exactly the same as before pregnancy, because your body has undergone a change (and it is for the better – you helped create a new life). Don’t let anyone make you feel fat or less attractive. Wear those extra lbs. proudly for now, and just live a healthy life with good healthy food and exercise, and you will be fine.