I made a post probably last month about this exact same thing. I'd always felt periods of flutters and was a bit anxious about them. Last month I actually "tested myself" when it happened as I wanted to prove to myself how I was probably overreacting. The sensation you described earlier about feeling the miss then that thud brought me onto a near full blown panic attack, was not expecting to feel it like that I thought it was all in my head. Needless to say a month later and my fear has focused onto something else and I'm not getting them every evening now. Apparently the thud is what's meant to happen, it's the process of the heart getting back into a rhythm but it does feel scary. Can you get a quick check up just incase? Dr will probably tell you all seems fine and that's usually enough to move past the worry.They persist a handful of times every day still. This morning they were totally absent until about 3pm. I was starting to be excited to move on. Then I felt a few dozen through the evening. Today was the first time I actually felt one while feeling my pulse. It definitely skipped a beat and then thumped harder. SO WEIRD. I’m ready for them to skedaddle.