How old is she? Babies and kids go through all sorts of phases, so I wouldn't take it personally. My son tells me every night that he wants daddy to get him to sleep because he knows that if Daddy gets him to sleep it means that Daddy will fall asleep and wind up sleeping in bed with him. If I get him to sleep, I don't stay.
There might be something else going on. Do you snore or talk in your sleep? It could be that you scared your daughter without knowing it, and she's reacting to that. It could be that she's expressing some independence, too. It could be anything, it could be nothing, either way, take it as a compliment. If she wants to be by herself to sleep, take it in stride knowing that you did everything you could to teach her that you would always be there for her, which gave her enough strength to be independent so young!.
Hmm. Is she trying to change her nap routine? Maybe she just isn't tired and is ready to drop one of her naps. How many times a day are you trying to get her to nap?