Need some advice! 15w3d

I have been picking up the babies heartbeat since 8w4d, as soon as I hit 14 weeks I haven't heard it since, I'm now 15w3d and I still can't find it on the Doppler, can't even hear the placenta through the Doppler.

Emerg is crap here, waited 3 hours on Friday last week and there was still another 3 hour wait so I left, I've had no bleeding, no cramping. But this is unusual, with my first pregnancy I heard my sons heartbeat on the Doppler and placenta throughout the entire pregnancy. I'm nervous as hell, don't know what's going on or what I should do!