As a couple of pps have suggested, you could have an arrhythmia. The majority are not actually dangerous so nothing to panic about, but equally not pleasant, and my heart is perfectly healthy and completely normal ecg's the majority of the time - need to where an ambulatory monitor for a week or so to pick it up.
I'm very lucky and have 2 - SvT and AF, managed with beta blockers for years but they're not working so well for me now.
I often get the AF at night. Fast and irregular heart rate and my Apple Watch can detect it. Stress, alcohol, illness and lack of sleep are all a trigger for me.
The SvT is better controlled by the beta blockers and I don't get it as often. That is a very definite sensation, like being winded, before it kicks in. Heart races so fast you can see it pounding, chest feels like someone's sat on it, can't breathe easily etc. HR's normally over 170 for me, but 220 is the worst I've had it.
The recommendations I've had from cardiologists is to go to A&E if lasts over 30 mins (very rarely does) and to try the valsalva manoeuvre (used to work well for my SvT). Google it, but it's essentially like trying to pop your ears but putting that pressure into your chest - so a deep breath and and then pushing out against your chest rather than breath out for as long as you can. Used to stop my palpatations straight away.
Go back to gp if the beta blockers don't help things settle down. Whether it's panic attacks or an arrhythmia they should be improving it, but you may need a different dose, or different type. I have 5mg of bisoprolol, was looking at upping to twice a day but I struggle with fatigue so cardiologist referring me for an ablation procedure.