There seems to be some great stigma attached to fitting into your jeans straight after the baby is born.
Most of us can't and that is the truth. I remember being feeling quite flat about buying a new pair of jeans that were three sizes bigger than I had worn before I was pregnant.
Surprisingly, it didn't take too long to get back to sizes I recognized, but why put yourself through the stress, there are a lot of other cool and comfortable alternatives such as leggings, cargo pants, slouchy linen pants, and trousers with a thick elastic band of fabric around the mid section, can really give support especially if you have had a caesarian.
Or if you must wear jeans, because it's who you are, then put away the super skinnies for a while and opt for a more relaxed cotton/denim mix, or some of the new really flattering styles that hold in your tum and have lots of stretch. Or even a pair of Capri jeans with a longer (empire line which goes under the bust and great for breastfeeding) top, and some flats. That always looks classic and hides the muffin tops!
Further Reading:
https://www.peachymama.com.au/collections/post-maternity-pants-jeans
https://www.peachymama.com.au/collections/breastfeeding-t-shirts