Worried *update*

I’m 8 weeks pregnant. At 6 weeks I had an US and the baby had a heartbeat of 100. I also have low progesterone levels and have been taking 200 mg of progesterone every night.

Up until a few days ago I had no bleeding and minor cramping. A few days ago I had light bleeding after sex and after reading a lot of posts most people said light bleeding was normal and not to worry. Since then I’ve had very little light color blood when I wipe. Today I have had cramps and back pain accompanied with darker but still not bright red bleeding.

I have an appointment at 8 am but only for an US. Should I go to the ER or does that not make sense?