As for the pants, elastic, stretch, drawstring, are your friends for now! You may want ot keep wearing you maternity pants, or use one of those "belly bands" they sell to help hold up the regular pants ( bonus, they help cover your tummy while pulling up a shirt to nurse). Good luck you will recover somewhat, if you work at it, but our shapes are pretty much forever changed by pregnancy, hip size changed, c-sections give you a poooch, and it can be reduced, but it does take lots of work - I have had 2 c-sections, and haven't been dedicated enough to lose the baby weight, let alone work on the pooch, so, I just live with it.
If you get a sundress with strapps, not sleeves, you can just slide one strap off your shoulder to only expose that side, or stretchy wrap style dresses work well. I almost ALWAYS wore a nursing tank top under all my clothing, that way no matter what you were wearing, your tummy was covered while nursing - you will get better with more and more practice.
Here are some great nursing clothing: