Am I having a miscarriage?

I’m currently six weeks and I started having vaginal bleeding. It’s not consistent and it’s not very heavy. No cramps or abdominal pain. However, my gestational sac is flattened and there is no heartbeat detected. There is still an embryo though. The doctors haven’t ruled it out as a miscarriage, but it doesn’t look too good. I have an appointment with them on Monday. Has anyone experienced this and we’re still able to have a full term ? Or is this going to be my last few days with my baby?