I saw my OBGYN today and couldn`t hear the heart beat of my baby. I am 9 weeks should i be worried?

My OBGYN today used a doppler and a mini ultrasound machine. With both devices he couldn`t hear the heart beat of my baby. I am really worried, this is my third pregnancy and never experience with i am going through right now. I don`t have any bleeding or cramping. He booked me an ultrasound on Friday but i think i`ll go crazy until then. I am so worried because i asked him how worried i should be. He said 75% out of a 100%.