Someone please help...PLEASE

At the beginning of June, I had a missed miscarriage. It was my first pregnancy, and like most people I was completely devastated. Our first ultrasound all they could see was a yolk sac and a gestational sac. We were sent home, and told to come back in two weeks. That’s when we found out that baby had no heartbeat. I was around 8 weeks. They never told me I had to come back in for a blood test so I just passed everything and hoped that I was okay. Well, I never did start my period and I finally got blood taken and found out I was pregnant again on July 29th. We went in for an ultrasound and the baby was 6w4d. We heard a heartbeat but it was only 119. Is that too low? Now I’ve just been sitting around feeling most of my symptoms go away. I’m scared we may have miscarried again. I go back for an ultrasound on the 19th, and I’m just trying so hard to stay positive and hopeful.