Missed miscarriage

I had an appointment on October 3rd. An ultrasound was done first. They tried a regular ultrasound and had to do a transvaginal due to not being far enough along. During that I found out the baby was measuring 8 weeks 4 days, my uterus was tilted, and it looked like my uterus was contracting. She didn’t tell me anything else just did the ultrasound and measurements then sent me to the waiting room for the actual appointment with the Ob. I wasn’t weighed or anything and was just brought back to an office instead of an actual room. I was told there wasn’t a heartbeat and I was having a missed miscarriage and have three options for expelling it. Dnc, pills, or wait it out. I am 9 weeks today. My body isn’t showing any signs of going through with the miscarriage on its own yet. How would I measure when I had the miscarriage? Would it be the day I actually start bleeding or the day of my appointment when they told me there wasn’t a heartbeat? And is there a chance that they just didn’t catch the heartbeat? If this is a miscarriage it will be our fourth one.