Saggy breast

I’m 20 years old 6 months postpartum, I breastfed, exclusively pumping due to issues, for the first three months and after that it’s been strictly formula. I’m not sure if it was because of the pumping but I had an oversupply in the beginning my breast would get full almost every hour and I was pumping 5 or more ounces out of each breast when my baby was on 3 weeks old. Anyway my breast are completely flat, I had great boobs before I got pregnant and during pregnancy I was a 34dd so they were big but nice. Now they are small and there is no elasticity. I can literally pull them and stretch them so far. Will they ever go back? Kinda ruins my self esteem I’m only 20