So sorry you have to go through this. I know how hard it is, i went through exactly the same thing last year. Ended up having an emergency d&c because the bleeding started suddenly and very heavy.
It was very hard for me, but getting pregnant again soon after it happened helped a lot. Now my due date is the same day as the d&c, one year apart.
I know it doesn't look good but keep positive, keep eating healthy and getting in enough nutrients for both of you. You said there is growth, maybe the days/weeks are off too. Some don't have a heartbeat for 13 weeks or can be found on the ultrasound for 13 weeks either. Hope for the best for you.
Doesn't sound good. My last miscarriage, I've had 6, baby had died the day of the ultrasound at 8.5 weeks. I was devastated. I went in for 2 more ultrasounds at 10 and 12 wks, still no heart beat but uterus was growing and hcg levels increasing. As hard as it is just stay positive. There was something wrong with the baby not you. You're very fertile after a miscarriage so you still have hope. Just chart so you know your fertile window. Ask dr for progesterone next +hpt maybe it was a luteal defect, it can't hurt.