Hello and thank you for using HCM.I carefully read your question and I understand your concern.
I will try to explain you something and give you my opinion.
Palpitation has to do whith rhythm issues.It might be a
sinus tachycardia meaning that the heart beats over 100 beat for minute.It might be an extrasistolic beat or other kind of arythmia.All of this cause palpitations,
shortness of breath, anxiety sensation.
Rhythm issues might have different causes like anemia,
hyperthyroidism, electrolyte imbalances,
cardiovascular disease, active infections or just stres.
In your case, as you have lost blood you might have anemia causing this symyoms or an active infection.
So, if you experience palpitation once a while you can wait, they're not an emergency.
But, if you feel irregular, chaotic heart beats and important shortness of breath than I will recommend you to seek medical treatment directly to emergency room.
You might have an electrocardiogram there, have a fool blood analyze and a cardiac echo.
After if this result normal hou can take time to have a holter rhythm monitoring to see your rhythm tendency day and night.
Hope I was helpfull.
Best regards,Dr.Ervina.