Woke Up With Palpitations - I Sometimes Take Metoprolol For

Woke up with palpitations - I sometimes take metoprolol for PVCs (benign according to cardiologist). I took 100mg metoprolol about an hr ago but now my heart rate seems very low and feels irregular - varies between 40 and 60 bpm. My blood pressure is 129/75 according to electronic Omron wrist monitor i use at home. Feeling anxious about this so I took .25mg xanax for the anxiety. Any advice/insight would be appreciated. Anything I Can do to get my heart rate up to normal range?