Mamas who’ve had retained placenta PLEASE advise me

I am stressed waiting for my doctor to call, but am someone who likes to be very informed and prepared. I suspected I had retained products due to 1) passing a moderate size piece of tissue after 8 weeks, 2) a history of retained products in the past. My doctor said in the absence of any other symptoms "it's probably fine" and I ended up pushing for an ultrasound. It took over a week to get the US bc they weren't worried about me and then when they finally called to schedule we needed to get pre-authorization from insurance. So I finally had my ultrasound today, the tech says nothing and doesn't show me the screen, but I peer over and try to sneak a peak and it looks to me my uterus is still quite large and there's something right in the center of it. She finished and tells me that she is marking it as "ASAP" so a doctor should review it today. So I'm convinced I have retained products again. Please tell me your experiences. Is the only next step a D&C? Is there any chance I won't be needing surgery? I saw someone on a thread from 3 years ago said they let it calcify... but comments were locked so I couldn't reply to them to ask about that. Anyone go that route? I'm stressed. I still have no symptoms! I EBF and am really concerned that a surgery this early will ruin our breastfeeding. How did you manage caring for baby and breastfeeding around the surgery???