Miscarriage ultrasound

So I was 7 weeks pregnant when I started getting cramping and spotting heavy this last week. Eventually globs came out and a couple days later the spotting and cramping stopped. I called my doctor and we have an appointment for this coming week to see if I did in fact miscarry. However, if the sac and baby were the globs that came out how will they be able to see if I miscarried since I was only 7 weeks?