K.J.
My daughter just started sleeping through the night at 15.5 months, so I know how hard it can be to go without sleep for so long. We had different issues, so I'm not sure I can help much. What really helped us was her becoming attached to a lovey. Now, this was much easier said than done, but it finally happened. We had tried since she was 6 months old to attach her to something, but she never took really well to anything. Then, about 1.5 months ago, she randomly decided to fall in love with a stuffed giraffe we had bought her at Christmas 6 months earlier!! She had completely ignored it until that moment, but now it is a life saver. I would try to get her to attach to something if possible like a blankie or animal. My daughter also loved the Fisher Price Soothing Sea Horse.
I would also say that she needs to tough it out a little. I don't believe in crying it out per se, but something similar would probably work. It might take a while, but instead of giving her a bottle, just go in and try to soothe her yourself without the bottle. She will probably be very mad at you, but if you are there for comfort, it might help. Also, our doctor told us that when my daughter was still nursing in the night beyond when she needed food to try giving her water. The theory is that when she wakes up for milk and only finds water (which they normally won't want), they figure it is just better to stay asleep. Whatever you do, do not give in and give her a bottle, not even once. That will mess everything up that you have worked so hard for. Just stick with it and do whatever you feel is best for your baby and your sanity.
Good luck, momma!! I hope you get some sleep soon!!
Edit: I also wanted to add that while it may be a 'mistake' on your part, we all have to do what we can to make it through the first year in one piece. I have done so many things that other people considered mistakes because I would have to break the habit later. However, I don't regret any of them, because my daughter and I both made it through the first year alive and healthy, even if I was only hanging on by a thread. ^_^ Don't knock yourself and just take it as it is. Good luck again!