Leah is doing this and has been since last december. Back then she was having nightmares/terrors and would come running screaming into our room and the only way she would setle was to hop in with us (and still it was taking up to a couple of hours some nights to calm her down) but if I tried to take her back to her own bed, even if she was asleep she would wake screaming again. At that stage we had a 4 month old who was alreday sleeping through and didn't need both of them up crying for hours!
Now the nightmare have stopped but she still comes in....now its a habit and its very hard to break it, also we are really soft and can't cope with locking her in her room. (we tried it and lasted about 30 mins and by that stage she was so upset it took a couple of hours to settle her). Some nights she goes straight to sleep and wakes after us in the morning, other nights she has dreams and keeps waking.
Sorry....no help to you, but your not the only one going through this at the moment.