Am I morally obligated to pursue a career in medicine?

I am a high school student who has no formal training in philosophy, so I apologize if this question seems naïve. However, it is one that I am currently facing in a life decision, and I would like a philosopher's input on the matter. I am nearing high school graduation and, as a result, will need to decide on a university major in the near future. My interests lie in physics, mathematics, and computer science, and I find it likely that I will major in one (or more) of those fields. However, it occurs to me that I might contribute more directly to the preservation of human lives if I were to major in, say, medicine or biomedical engineering. I think it would not be controversial of me to claim that more people have been directly aided by vaccinologists than algebraic topologists or string theorists. I have no immediate objections to majoring in medicine; in fact, I believe I would have no problems with the coursework, and could one day become a competent medical professional. However, I suspect that I would be less satisfied with a career as doctor than as a physicist or mathematician. Even so, by an elementary utilitarian calculus, it seems preferable to me that one person be slightly less satisfied with their life than someone die due to a lack of available medical attention. My question, therefore, is the following: given that I am capable of becoming a competent medical doctor, am I morally obligated to attempt to become one?