Hi Casper,
I've had bad anxiety for a long time now. Heart palpitations are a common side effect of anxiety and can be very frightening.
I used to lay in bed at night unable to sleep because my heart would be beating so hard and fast that it felt like it would come out of my chest.
Heart palpitations are also a common side effect of smoking marijuana. They will generally only last a short while. If they're still happening long after you've smoked then I don't think that's the cause.
Heart palpitations can also be a side effect of prescription medications. I had very bad palpitations at the beginning of the year, so bad that I ended up in hospital for 4 days and it was a prescription medication I was taking at the time.
There are medications available that slow down the heart rate to a natural rate. You'd have to speak to your GP and ask his advice. I was prescribed them and I've found them to be very helpful.
Breathing can be also be very effective. Practice breathing slowly, deeply and evenly when they're happening. That helps to settle mine down as well. You can look up deep breathing techniques online.
Also when they're happening, don't feel your heart with your hand or check your pulse. This will only make you more aware of them and in turn get more anxious which makes them worse.
