Embryo only grew 3 days in a week

Not sure what to think of this pregnancy. My hcg was slow to rise, didn't spike until my fourth draw. Then I started spotting and bleeding. Had my first US June 12 which was 6w1d. The embryo measured about 6w. Okay. No cardiac activity but it was early. The Dr said I had a subchorionic hematoma (I had this with my last miscarriage) and that the embryo looked a little weird. Went for another US yesterday convinced there would be no heart beat but there was! The embryo only measured 6w3d though. It only grew three days worth in a week. The subchorionic hematoma is still there but is not large. The Dr. said the pluses are that it did grow and it has a heart beat. Anyone experience this? I don't know what to make of the growth. I will have another US next Friday. This is my 5th pregnancy and I have lost the other 4 before 8 weeks. Thoughts and prayers also welcome <3