Low Heartbeat and a Week off?!?

lelt04

Hi everyone, so I'm really scared. Last Friday I had an appointment and I was supposed to be 6 weeks 3 days. They did an ultrasound but could only see a yolk sac. So I had a follow up appointment Monday (yesterday) afternoon, and I should have been 6 weeks 5 days. They saw a fetal pole and an itty bitty baby that measured 5 weeks 6 days. They measured the heartbeat and it was only 80-87 bpm. They said maybe my dates were off which I would be okay with but if they were really off a week, I would have had a positive pregnancy test 7 dpo and would have conceived when my husband was out of town (which DIDNT happen lol). So anyway, I am going back in Friday to see if there is growth and a stronger heartbeat but I'm just SOOO nervous. I just had a miscarriage at 8 weeks in February and feel like I'm going to be going through it again. Has anyone else seen a really low heartbeat like that? If so, can you honestly tell me what the outcome is? I just want to be prepared emotionally. Thnkas!