Cheating on My Doctor

I was planning on using the same doctor (Dr.A) my sister had for her latest pregnancy but because I had my first checkup (with a nurse) before letting my family know, I just picked a doctor (Dr.B) for the time being. I know I can switch doctors anytime and I'd prefer to switch before I actually meet Dr. B but my blood shows I may have TB. I've been referred to a different doctor, at a different clinic to get tested for TB but now I feel an obligation to stay with Dr.B for prenatal because of this. What should I do?