While there's nothing wrong with sharing your bed with the dog, you reserve the right to kick her out. If sleeping together just isn't a good fit anymore, gradually removing her from the bed and giving her an alternative is the key to getting a good night's rest again.
Give your persistent pooch an alternative to your bed. Now, your dog isn't stupid. She knows that a little doggie bed from the pet supply store is no match for your mattress, and she may resist. One big factor is the comfort of sleeping with her owner, so ease the transition by placing the dog bed up on an elevated surface so she can see you. Ideally, you should be able to reach out and touch her, but her bed should be far enough that she can't make the leap onto your covers.
Make bedtime a routine for your dog. Dogs learn through consistency, and only through consistency. That means if you give in and let her sleep in your bed every now and then, all of your training is undone. With that in mind, establish a nightly routine for going to bed, so she knows the signs that the night is winding down and she's going to be retiring to her own, private bed.
Reward her with a nighttime treat, like a special toy she only gets when she goes to bed. This distracts her at bedtime and also gives her a way to occupy that lonely time without you before she falls asleep.
Lower your dog's bed gradually, if it is elevated. By this point, she should be used to sleeping in her own bed, so you want to slowly move it further away from your own bed until it's positioned where you want it.