Doctor appointment review

Hello ladies just got out of the doctors I'm 5 weeks pregnant they did an ultrasound and couldn't see anything they told me the uterus is getting ready for baby but they have to do hcg blood work to see if the baby is growing and all that stuff so scared at this point I'm trying to have a positive outlook anyone's gone thru the same input is very welcome how many weeks were you when you saw something or heard a heart beat ?