I have been in a similar situation when I went into fast AF which was thought to have been brought on by a hip operation a week or so beforehand. I was taken into coronary care to be sorted out. After that, and still, I have had bouts of SVT, which is a very fast heartbeat, and I use the ploys you have outlined to make it stop. It is much worse on lying down.
I am told that it is not of concern if it is not frequent or continuous. It seems to be common in older people. I believe that it is also more common in those with gastric problems. I have learned to live with it and do not worry about it - in fact my OH worries more about it than I do! And the GP has been very clear that if I go into AF again I should seek help.
If you have only had those two episodes and the GP is not concerned then it might be best to wait and see, but get back to him/her if it happens a lot. I do however understand how very disconcerting it is. If it is really bad then 111 is an option - my GP said if it was very bad I should get an ambulance simply so the paramedics could do an ECG and get a clear indication of what is happening. Mind you, it would probably had settled down by the time they got there!
Another useful ploy is to cough - that does it for me sometimes.
Watch and wait seems to be the thing.
