If the sling hurts, chances are it's not on quite right or it's not the right size (if it's one that comes in different sizes). It's a pretty common mistake. It can be tricky to get it just right over the shoulder unless you have someone to show you how. My sister makes slings and she recommends http://www.mamatoto.org/ to help with learning how to sling.
And different slings fit differently. I had a carrier I got at Babies R Us the first time and it sucked. It hurt so badly. Then my sister made me a ring sling and it made all the difference in the world.
I'm glad you've been able to find ways to juggle the kids. I promise it really does get better over time.
I hope you heal quickly. I've never been able to sit still, so both times, I made myself bleed more than I have to. The first time, my OB didn't tell me my activity level had anything to do with it. Second time, after I did it again, my midwife told me to make sure I rested as much as possible. I did and it really did help. I hope you get as much rest as possible and that you're better asap.

Tonight was better. While I made John drive an hour to pick up a swing and a sling I found on Craigslist supercheap, I managed to give Jonas a bath while Jules slept in the baby papasan. The sound of the running water had him out cold. Total baby Ambien. It was awesome! Then, when John got hom with the swing, I put a wide-awake-Jules in it and again - out cold. I used to jokingly call swings "Neglect-o-matics" but I can see now that it may be the only way I get two free hands to make Jonas lunch and whatnot. I'll give the sling a try tomorrow. I've never been a huge fan of them because the first one I had hurt my back - but I never really gave it an honest try.
This might not be sooooo bad after all. I'm just still really concerned about the bleeding. It's not enough to rush to the ER, but it's certainly more than I should be having right now. I'll feel much more confident when I'm all healed up down there. Tick tock tick tock.

Do you have a sling? They can make life SO much easier when you have a newborn especially when you have older kids.
One tip I heard for older children is to make a point of, when the baby is sleeping or otherwise occupied, playing with/talking to the older child and saying something like, "No, Baby. This is my time with (older child)." It's supposed to help show the older child that they really do get some time of their own.
A friend of mine had a big brother party for her oldest. It was to celebrate him becoming a big brother. She invited over some friends (i.e. my kids and me) and we had cake and party hats. He got a gift from his baby brother too. It was SUPER low-key--nothing fancy.
I hope things get easier quickly.

I can identify with all of this. I just had my second, 3 mos ago and felt so bad about the fact I don't have that one-on-one time with my 2 year old. I'm not sure it will ever be the same, but it gets better (or maybe just easier) with time. At least, that is how it has been for us.