If you are living in the US or Canada (I don;t know the standards abroad) I would think you have a basis for writing to your local medical board about this "Doctor". If he is a Doctor, in my opinion and based on the very short note you wrote it would appear he crossed the Doctor Patient line and he should not be practicing Medicine. What he did sounds to me as though it was a blatant violation, I would not call it rape but I would certainly call it abuse and manipulation and a violation. Under no circumstances should he be having sex with patients. And based again the the little note you wrote what he did could not begin to be considered tantra. This man is an opportunist, a pig and a fool and you have every right to complain to the proper licensing authorities. Because you did not protest I do not think it rises to the level of rape, you put yourself in an inherently sexual situation without enough information, without setting any boundaries and that is unfortunate and it is terrible that you were subjected to this but I think rape is not legally what he did. Ethically and morally I think you could call it rape. And you should absolutely contact authorities, if he has done this to you he will do this to others. You owe it to the next woman client that he may attempt to manipulate to come forward. Assholes like this give men a bad name. Please contact someone, legal aid, a woman's crisis center or rape helpline. They should be able to help you get the emotional support you need and guide you on how to report this man.
Call a girlfriend if you need moral support to help you through but please do it.