20 weeks and no heartbeat

Ashley • 29, married, mother to 7 year old boy and angel girl👼
I'm completely torn apart.
2 weeks ago we went in for an ultrasound and they discovered fluid around the baby's liver and abdomen. They then had a whole blood work up done on me to find out if it was being caused by virus or something chromosomal. They told us the cause could range from nothing to something way more serious. After waiting a week they sent me again for an ultrasound where we found the fluid hadn't gotten worse, the heartbeat was strong, all the tests came back fine but they still wanted me to come in weekly to check the baby. That day we found out it was a girl.  Yesterday I started to feel movement and I was so excited bc I thought "I made 20 weeks and there's movement this has to be a great sign!" We went in for our ultrasound today and found that there was no heartbeat - the baby had passed.
I'm feeling so guilty and confused and sad and just everything. What if the movement yesterday was the baby in distress and I didn't know so I was celebrating it? What if I should have called the doctor? Idk.. So here I am. In bed. Waiting for an appointment to be prepped for the surgical removal tomorrow morning. I'm heartbroken. We just picked a name and started making plans on buying everything and redoing the nursery. 
I just feel empty..