Well if you are meant to be a Nun God will show what to do in his own good time. If you have that in mind you need to be attending Mass as often as possible, Confession at least once a month- weekly if possible! Devotion to Our Lady is most important & also Eucharistic Adoration.
I am in the process of becoming a Monk so like you I have been through times of thinking “Oh am I supposed to do this? Should I do this…?” I know what you are going through! I think that you need to really think about what is more important to you being a doctor (which is a very special and great vocation) or trying your vocation as a Nun. There are many different Orders in our Church- many with medical backgrounds just as an example the Missionary Sisters of Charity founded by Mother Teresa. However, if your intention is to become a Nun it cannot be in order to be a Nun who is a doctor. It may be possible for you to do both and as you have that gift am sure you would be able to use it- however thinking “Oh yes I will be a Nun if I can be a doctor Nun” is not the right train of thought. If you enter the Convent it is to be a Nun first above all, even if you find an Order of Medical Sisters after completing your studies and making vows the Sister Superior might decided “Oh yes Sister…although a lover of medicine you are also a great cook, therefore, I will give you the job of Convent cook”–(eg. ) and as a Religious sister you would have to obey! My friend who is a Nun was in exactly the same position as you and joined the female branch of the Trinitarian order- the one I am joining (however in the male branch) and before her final vows was told that she couldn’t be a nurse and that she would teach in a school owned by the Order- and she was bound by her vow of obedience.
Therefore, pray about it, think about it and when you are sure which path you wish to follow more and what your heart desires most then God will show you the true path- which could be either, however becoming a Nun is to serve God first and others second- in the religious life that is most important. You enter the Convent to be a Nun not a Doctor. There is a very good film which would be perfect for you (you may have already seen it) it’s about a Nun in exactly the same situation as you! The film is called “The Nun’s Story” starring Audrey Hepburn- I think you can watch it on Youtube. I hope that is a fair answer and I promise you my prayers for you and ask if you would pray for me to. Although in the film she decides to be a Doctor over being a Nun but still haha it might give you some idea- it’s a good film!
God bless you!!!