Help! Worried mama :(

So today I had my doctors appointment.

On here I'm a lil over 11 weeks. Which at my last doctors appointment I was told I'd hear the heartbeat.

So I'm super excited because I haven't heard the heartbeat or have had an ultrasound yet. So I get there the doctor I normally see was sick so they had someone else. So she says ok so your a lil over 11 weeks let's measure you and try for the heartbeat on the doppler. So she measures me and I ended up measuring 10 weeks.... I'm like ok so we try for the heartbeat and she seriously goes back and forth and pretty fair down looking for the heartbeat......nothing.....everything she finds she says it's me and she seemed to get nervous and starts saying Oh well you are measuring 10 weeks so maybe the heartbeat isn't that strong yet blah blah blah and in my head I'm thinking that with my son we heard the heartbeat at like 8 weeks.

So now I've been worried all day thinking that something is wrong or that I'm going to loose the baby..

Anybody else have been in my shoes?? When did you hear the heartbeat?