My DD did almost exactly the same thing at almost the same age- we ended up just putting her in her cot and patting and singing to her, once she got used to that we decreased the amount of time we stayed in with her. So to start with we would pat and sing her to sleep, and as she got used to it, we would pat her till sleepy, and then just a quick song and pat and we could leave her to fall asleep on her own. It did take a little while to get her into the new routine, but it was awesome once she got it and started to self settle. Good Luck!