so I'm a little worried about my little's heartbeat...I have a doppler that I use at home and…

so I'm a little worried about my little's heartbeat...I have a doppler that I use at home and earlier today I went to listen and it sounds like every five beats it beats oddly about two times... Like bum bum bum bumbum bum bum him bumbum if that makes sense? Lol I haven't had any problems this pregnancy and his heart has always been good and strong, structurally sound, etc. I've been checking it about every two hours since I heard the oddity earlier today and it's still doing it 😕 should I go to the ER for peace of mind or am I over reacting?