Does Black Spot In Ultrasound Indicate Pregnancy?

Hello. I have wished a gynecologist and he says he sees a black spot through the ultrasound. Does that mean I am pregnant? He said there is a 70% chance I am when he sees that. is that really so?.My period is suppose to come in 3 days . is it too early to take the early home test alone? The doctor took my blood and I need to wait still 4 days. What to do? How to protect the fetus when I am really pregnant?