What are the chances of having a miscarriage after hearing a heartbeat?

I lost 2 babies in the past due to ectopic then a chemical this is my 3rd pregnancy first time I’ve ever heard a heart beat at 7 weeks and 1 day and it was strong my ob wasn’t really concerned about anything now I’m 8 weeks and 3 days no bleeding or cramping so far my pregnancy symptoms are on and off but just because of my past losses I get scared and terrified that something might go wrong 😔