Dolls can be scary and they can also be lovely, it all depends on the type of doll and the way you feel about dolls in general as well as what time period it comes from. If you have a dream about dolls it might be a nightmare or it might be a wondrous dream. It all depends on your own feelings on dolls.
If you have a dream about a doll this can mean a few different things, but the tone of the dream here is really important to interpretation. There are a few different tones that a dream like this can have too, but generally these tones will range from a tone of anger and unhappiness to a tone of fear, to a tone of childlikeness to a tone of happiness. If you have a dream in which you see a doll, all you need to know is the tone and then you will be able to interpret.
If the dolly that you saw in your dreams came up in a tone of fear then this means that you are scared of something. Dolls are known for being extremely scary to some people because they can seem like small people and the more real they are the more fear they inspire. If you have a dream of a frightening doll or a dream in a frightening context then this means that you are just generally afraid in your waking life of something else, some icon or person that is frightening you and causing you to have nightmares. Another option is that you are having these dreams because you are scared that someone is going to hurt you and you won't know it until it is too late because they are so stealthy about their dealings. This could be referring to an emotional or physical wound.
If you have a dream in which you see a doll but it is not a frightening dream and you are seeing the doll in a good context then this usually means that you are doing a good job of coming to terms with your desire to revisit your childhood. Revisiting childhood is something that just about every adult will want to do again at some point in the future because childhood is such a positive time for so many. If you spend a lot of time brooding over childhood or dreaming about a doll, dolly, dollhouse, doll baby, doll head etc then all this means is that you are now at a stage in life in which you are interested in returning to your childhood. Of course this is physically impossible so you should not fixate on this too much, but it does mean that you can try to regain that childhood in a few small ways.
Go out and do something that you once thought was fun when you were a kid, something that it would still be appropriate for an adult to do. Go out and buy a gameboy or have a run. This type of dream can also mean that you are yearning for a child and the best way to relive childhood is to have a child of your own. It may not be feasible for you but you should consider it at some point.