I used to breastfeed on the bed lying down and then slid DD off and then gradually left the bed. We co-sleep so a Queen size gives ample room. I would try a toddler bed so she does not feel the movement and the loss of your body heat so quickly. We have only recently stopped bf to sleep but still stay with her holding her while she falls asleep. It is beautiful to watch her slowly slip into peaceful sleep land.

Good luck.