Ultrasound

I went in for my first ultrasound this past Monday. I was supposed to be 5w3d however the ultrasound tech could barley make out a little blip in my uterus that only measured 4w6d. They did not think my HCG was high enough for a gestational sac yet. My overies and tubes looked clear and my blood vessels in my uterus are juicy and fat. All the signs point to a intrauterine pregnancy. I go for a repeat ultrasound in 2 weeks and I am trying so hard not to stress myself out. I had a MMC the end of December and a D&C in January. This is my rainbow baby and I just want everything to be okay. Any advise or similar experiences anyone could give me would be wonderful!