I joined graduate school in the US with interests in theoretical chemistry/chemical physics. Though I was enrolled for a PhD in chemistry, I was taking classes in physics for an entire year. This made me realize that I was more interested in physics related research than my current work in theoretical chemistry. While I was still in a dilemma, I convinced myself that I should continue in chemistry and joined my current advisor's group. Things were going fine for a while until I ended up having a minor confrontation with my advisor that made me feel sick about myself. I didn't know some of the basic things he was asking me and I was left stupefied by him. This made me think if I really wanted to pursue research in this direction. As a reaction to the flashpoint I had hit, I approached another professor in the physics department. While he rejected my request, he also notified my current advisor about my intentions. I really didn't mean to hurt my current advisors' feelings about this but, I was dumbstruck when he confronted me about my emails to another professor and accused me of unethical behavior. I am really confused about what to do with my situation. There have been a few students who have had similar issues of feeling disconnected from their research in my current research group, in a case even one of them switched to another group abruptly.
What should I do if my current advisor decides to step down?
Edit
How do I really find out what I am passionate about and is there a way to separate the reality from noise?