Spotting 5 weeks and 3 days

Sara

I have been spotting for almost two weeks. I have been to the doctor to confirm HCG levels and even had a an ultrasound to see the sac at 5 weeks 1 day. I asked about progesterone levels and the doctor told me he doesn't test for that during a first pregnancy. But couldn't low progesterone levels be the cause of this spotting? Should I get a second opinion so I can possibly prevent a miscarriage?