i have been there. i nursed all my kids to sleep and it definitely does create a sleep issue. i dont beleive in cio either, i never did it with either of my first 2 kids, i was just up with them all the time, and a lot in my bed. my first is 7 now and he still comes in my bed almost every night. im certainly not saying thats unavoidable, my daughter (almost 5) was in my bed all the time too as a baby, and now she almost never comes in. though maybe thats because my son is already there, but i dont think so, she just likes her space.
......aaaanyway, by the time my 3rd baby was about 10 mos old, he didnt sleep for more than an hour at a time. ever. it was a gradual thing, we were doing just what you are doing and it just got worse and worse until we were down to about 5 hours of sleep total in 24 hours, and no more than an hour at a stretch. it was awful, really, for everyone, and certainly unhealthy for him and i, i was really crazy. plus i had watched some horrible news clip about a mom that rolled over on her baby in bed and killed him, she had been on medication and was fairly overweight, but i couldnt get it out of my head so that was the end of that for me. so, out of desperation, i let him cry it out when he woke up. it took 2-3 nights. i wont lie, it was awful. i still dont believe in it, i think it stinks, i stayed in the shower and cried most of the time while he cried, horrible, but... it worked. after that, he slept better than anyone. i still nursed him to sleep in my arms and put him in, but when he woke up i didnt go in, and he very soon stopped waking up (or woke up and went right back to sleep like we all do). he slept great. he still does. he is still in the crib, i have a crib tent and he goes in, hugs and kisses me, tells me "I zip it up!" and he zips himself in, lays down and goes to sleep, its like a dream, he is going to be 3 tomorrow. it was the first time since i was preggo with my first son that i slept. so, that was my experience... just saying..... lack of sleep is a real problem, its truly unhealthy for everyone, especially the baby, thats when they grow and brain development and all that good stuff. and the damage its doing to you isnt helping you to be the best mom you can be. so if i were you, i would try everything else you can think of, take other people's advice, you never know what will do the trick. (i was still nursing my daughter when i got pregnant with my 3rd, the doc told me to stop nursing her and she was soooo not ready to stop. she didnt know any other way to go to sleep. so i bopped her to sleep in that boppy seat for over an hour every night for a year, until she was so big that it didnt even bop anymore, she just layed there on the floor in it. i swear my left calf is still bigger than my right from all the bopping. ) so, like i was saying, my advice is to try whatever you can, but dont rule out cio if it gets bad. if you go that route, it wont be the last time that you do something you dont believe in for the sake of you and your childrens well being. i wish you the best of luck.