Am I experiencing medical racism

So today I got another mammogram and a breast ultrasound . During the ultrasound they asked if I had any immune issues and if I have any black in me. I’m 60% white and 40% black and they said black women have bigger lymph nodes than white women. My question is how do they know which side I got my lymph nodes from? They started just saying I’m a black woman after I said I’m both black and white. I’m scared like have they checked the size of biracial women’s lymph nodes? Anyway, I don’t want cancer because of racist stupidity what should I do professionals?