anyone experience a missed miscarriage?

I got 4 clear positives on pregnancy tests and when I went in today, they said based of my bloodwork, I'd had a missed miscarriage, that there was a baby but it's likely not viable now. I should be 5 weeks. They want me to come in for an ultrasound in 2-3 weeks to see if perhaps there is a heartbeat or if I haven't naturally miscarried by then, they would give me some medication to begin the process. Anybody been through this? I just don't know what to expect. My heart is breaking and it breaks more everytime I'm reminded of the false hope that perhaps they're wrong, the chance that there could be a heartbeat, but knowing there's no hope. I just don't know what to do, how to grieve. The father doesn't even know that I was pregnant yet.. 😓💔