I have to agree with the previous poster, only you will know your own desires and needs, it is essential however to be true and honest with yourself in respect of these.
I am definitely a dom, however I have been a sub once, and very recently, very very actually I have desired to serve another again. These feelings are strange to me, I do not think I am a switch, as I do not wish to exchange roles with this person.
I feel that perhaps one knows where one desires to be in certain relationships.
As mentioned I am a dom by nature, but in exceptional circumstances I have desired to hand my power to another.
Go with what you feel and do not get too fixated with labels, Oh and .......enjoy!