Is this a single PVC or a run of PVC

I'm confused, is a run of PVC a series of skipped beat, pause, thud, skipped beat, pause, thud etc.

Or is it small beat, small beat, small beat, pause, normal rythmn. No noticeable thud.

I get this what feels like a small beat, small beat, small beat, say 3 or 4 in a row, sometimes they are fast, as in a vibration, sometimes they are slower, then it feels like my heart stopped, then it comes back. Maybe its the ventricles firing a couple of times instead of just once. I don't know. I find it happens usually when I'm concentrating on something and I'm at rest breathing shallow. It feels like I can't breathe, but I can breathe obviously, and I still alive, no dizzy or anything.  So I quickly sit up straight and do a few deep breaths to get my heart rate up again and nice normal strong beats.

[Wisconsin2007]

The first thing you describe would be called bigeminy - the second thing you describe, the thing you experience, could be one of a couple things: either a couplet, triplet or NSVT (in each case, contractions initiated by the ventricles), or it could be a vert short burst of PAT or SVT (PAT and SVT are more or less the same thing), where the beats are initiated in the atria.

When the electrical impulse originates in the atria, it's almost always a benign condition.  When the impulses originate in the ventricles, sometimes it's benign, other times not.

Best bet is to get yourself on a Holter monitor or event monitor, get the events captured and have a cardiologist see the rhythms to diagnose the problem.  It's probably minor, but always good to find out for sure.