Over the past few months, i've noticed my heart beat getting stronger (no increase in rate, just significant pounding). what is this?

Skipped beat: Sounds like you're describing a Premature Ventricular Contraction (PVC), which feels like a short pause, followed by a single stronger beat. They're very common among otherwise healthy people and can be reduced by avoiding stimulants, such as caffeine. See a heart rhythm specialist (cardiac electrophysiologist) for further evaluation and to ensure your heart is healthy.