Can’t find babies heartbeat! Please help!!

I’m 8w6d with my second baby and I can’t find the heartbeat on my handheld Doppler. I had an ultrasound at 7 weeks and it had a heartbeat of 120. Is it too early? I’ve tried the past few days but I can’t find it and I’ve looked at YouTube videos of finding it. I’m just so worried. Anyone else experience this and found it later?