Oncology appointment.

My OB told me she was going to refer me to a hematologist due to my mildly elevated platelet levels. I get a notification in MyChart saying I have an appointment with an oncologist the day before I find out the gender of my baby. Oncologists usually deal with cancer. I'm freaking out. My papsmears always have come back clear and the last one I did came back clear as usual. Has anyone ever seen an oncologist while pregnant? What should I expect? I feel sick to my stomach thinking about seeing a cancer Doctor...