So upset

Km • 27. Married 5 years. Our daughter Stella Claire is our entire world. Born Nov 15. 2015. Pregnant with #2 due in April.
Doc heard a heartbeat at 10 weeks with Doppler. I bought one and heard it again this Tuesday and Wednesday and now nothing. I've tried twice a day for three days :( I'm so scared. It couldn't have moved much in a week, could it? Next appointment isn't until May 21 :(