​This is my first pregnancy, and I've been experiencing back pain and pelvic pain. I went to the doctor yesterday, to check that everything was right as I had three home positive test. I was asked to do blood work and urine test to confirm pregnancy. Blood and urine test show that I am pregnant. However, I am concern due to low HCG  levels? What does this really mean? I also had an ultrasound done to check for ectopic pregnancy, nothing was seen on the ultrasound. Doctor said that ultrasound did not detect a pregnancy cause it could be very early. Has anyone experience something like this? I am five weeks today.