Confused

The last few days have been a roller coaster of emotions. On Saturday I started having light spotting and by Sunday was bleeding and cramping. I imeddiatly called the doctor and figured I was miscarrying. I got a blood test that came back showing low progesterone and had an US that showed what a 4 week pregnancy looks like but I was estimated to be at 6 weeks. The doctor is now having me try to supplement progesterone to see what happens. I just don't know how hopeful I should be but I want to be so badly! I am still experiencing bleeding and cramps. The cramping seems much less worse than it did a couple days ago. Also have dull lower back pain off and on which I know is also a sign. Just looking for some insight.