I am right there with you. I had an emergency c-section with my first, too. Her heartrate suddenly started dropping, because, as they later found out, the cord was wrapped around her neck, and with each contraction, it was getting tighter and tighter. So once it started causing her to lose oxygen, they had to get her out of there as quickly as possible. The doctor told me afterwards that it takes 2 minutes to get a baby out with an up and down incision, whereas it takes 5 minutes with a side to side one, and she said we didn't have 5 minutes...it definitely makes me grateful for my sweet little girl.
But to address your question, I have had the same problem with my belly. After the first, it actually wasn't that bad, but I gained a little more weight with my second (who is almost 11 months old), and my stomach is so flabby now. I've actually lost more weight after this pregnancy, but my stomach is just a lot of extra skin. My husband is sweet enough to say it looks fine, but I feel like even when I'm wearing a one piece swimsuit, you can see where it indents in the middle. I do feel like it has gotten better in the last few months, because I have been doing Pilates once a week. That really seems to help me hold in my belly and stand up straight instead of just letting it all hang out. Also, from what I've heard, just holding in your stomach throughout the day is one of the best ways to firm up your stomach. So I've been TRYING to remember to do that, but I haven't been very good about it.
It's funny, because most women our age have had the side to side incision, so it's hard to get any advice from them, and at least in my family, all of the older women who have had the up and down incisions don't really seem to care anymore about their bellies...so they're not much help. But maybe there are some other older women out there who have had the up and down incision when it used to be that was all they did, and maybe you women can give us some advice on toning up our bellies.