Hello girls, my ultrasound showed that today is 37 weeks, but accordin…

Hello girls, my ultrasound showed that today is 37 weeks, but according to the doctor's calculations it's 36 weeks and 2 days. Yesterday I had back pain, my belly hurt and there was occasional cramping. I arrived at the maternity hospital, they checked again and there's no opening yet, but there is some discharge with blood and milk. The doctor said this could be a small plug coming off. I'm very worried because he says it should take another week to go into labor.