From your description, we have similar body types. It's really easy to get attached to a particular ideal of how we should look in a particular garment. When I feel glum about my saddlebags poking through the long slinky striped pencil skirt I have--even though the French employee thought it looked fabulous! where is the French sartorial brutally??--I remind myself:
a) I am strong. With children, you are much stronger.
b) I am healthy.
c) My partner still thinks I look great naked.
d) I look the most proportionate without clothing. Without clothing, my saddlebags are less noticeable and look normal and natural. When I removed the skirt, the saddlebags didn't seem so large.
If it's any consolation, small busts have lower breast cancer risks and will not sag noticeably with age. My DD single best friend can't wait to have children, so that she can breastfeed and then have her breasts reduced and lifted.
Sending you good vibes and wishing you much success on your health journey.