Been feeling what feels like an extra heartbeat that sounds like a thud.normal ekgs..normal echo..normal stress test and blood work? help?!

PVC or PAC: Most likely, you are sensing either premature atrial complexes or premature ventricular complexes. With a normal echocardiogram, resting ecg, and stress ecg, it is unlikely that you have any real concerns. These are benign. You should be able to determine this with either a 24 hour ambulatory ECG (holter) or an event monitor, but i'm not sure that you need to do any further investigation.