Miscarriage question TMI (No picture)

Brooklyn
So on April 1st I started bleeding, and April 3rd is when everything took place, but I have a question...
For those who have had miscarriages how long did it take you to find out that you miscarried after finding out you were pregnant? 
I had my 1st ultrasound on March 11th, and 3 days later the baby stopped growing, but didn't know until the 1st. So it took 3 weeks for me to discover that the baby wasn't going to make it. 
However I guess the ultrasound Showed that something was wrong with the yolk sac but they never told me. Do you think it was wrong of them to not tell me? I don't know. I'm just lost for words.