I'd also say go for it! I know when I was expecting my second, I couldn't imagine loving this new baby as much as I loved my first, and I was so sad for my first that she would have to share her mom, etc. I also didn't know when I was going to get the chance to rest, as I slept in most mornings with my first (after being up pretty much every hour with her all night) But it is the best thing you can do for a child, I think! Now they are so happy together, (most of the time ) They are learning to play together, and each one is happy to see the other, when one comes into the room. Having a sibling teaches a child sharing, self denial, compassion, and that the world doesn't revolve around them. These are all valuable lessons for your whole life!
Yes, there are some crazy moments. But I found out that God didn't give me more than I could handle. This second baby was a much easier baby, and I didn't need as much extra sleep time. And, there's always help available somewhere if you need it. (grandparents, your siblings, friends, etc.)
Your second delivery, also, will likely be much easier than your first. (although there are no guarantees) so hopefully your recovery won't take as long. And if it does, well, at least this time you'll know what to expect, and you can have some help lined up before hand. (ie. get DH to take a week or two of vacation around your due date, or have your mom or MIL come every morning for a little while)
Anyways, I would definitely say go for it! I don't think you'll here from anyone who regrets it. We're hoping to have lots more.
All the best!