CC is tempting but even the people who came up with the idea don't recommend it for such young babies.
If you have time to read a book have a try of this or this. If you don't want to shell out on a book try your library, these books are so popular around here that the libray has several copies of each.
Babies can get used to and end up needing to suck to go to sleep and/or sleep on a full belly. If you do want to start to get her self settling the No Cry Sleep Solution has some ideas particularly for your situation (co-sleeping/BF mum) they are quite subtle techniques but they do work for some
Sleepy don't think she is using you as a prop, but if its a problem there are lots of things you can try like trying to up her bfeeds in the day, getting someone else to try to settle her at night if thats possible or even night weaning. She is still so young though.
Sleepy I don't think you are doing anything wrong either. I did the same as you but have now moved my one in her own room and found that she sleeps much better. She is a light sleeper and I think I used to wake her. Also, when she wakes in the night, perhaps your DP can try settling her first? And if it doesn't work after a few minutes, by all means give her the breast. You really don't want to cause dramas during the night!
But I noticed that often just putting her on my shoulder for a minute puts her back to sleep. In the past I would not have given her that chance, she'd been straight on the breast!