Freaking out 😣

Ma
I went to the dr today thinking I was 6w. When they did the ultrasound the dr said the baby is a week behind.. there is a yolk sac but that's all he can see.. im trying to stay positive and figure out conception time. I had a very early miscarriage last month and my period lasted 12 days and then I got pregnant after that. I thought my conception date was 1/4 but apparently it was after... anyone else have this happen?? I go back next week and im so nervous... im even more nervous that I have no symptoms besides occasional nausea and extreme hunger.