Miscarriage experiences please!

I’m 7 weeks 3 days in my third pregnancy, last week my nausea and breast tenderness was insane, 3 days ago it just stopped, I’m way more energetic too and just don’t feel pregnant at all.

I had some blood 2 nights ago at 4.30am, red and quite a lot on the toilet paper, no clots, then all days it stayed brown and very light. Before I started bleeding I was having discharge that resembled mucus plug however I wasn’t too fazed as I know it can regenerate.

I spoke to my doctor who has concerns as there wasn’t a heart beat at my ultrasound where I measured 5 weeks 5 days. I have another ultrasound on Wednesday to check if I’ve miscarried however want to hear if anyone has experienced this.