Your symptoms do not sound like AFib to me... Untreated AFib usually results in a high heart rate, and an irregular heart rate. By high I mean a resting heart rate over 100 bpm.
I agree, normal heart rate goes up when we breath in, and slows down when we breath out. I think it is the body's attempt to get the incoming oxygen on the breathing in.
Did you EKG show a missing or depressed "P Wave"? If your "friend" didn't mention the "P-Wave" I doubt there is any real knowledge of what to look for on the EKG. Just my patient understanding, my EKG is always read by a medical doctor.
I noticed that at quite a young age, that when I did deep breathing, my heart slowed down. If I took long pauses, my heart slowed even more. However, as soon as I inhaled, up it went. I asked my Doctor about this at one appointment and he said it's normal and a good sign. A healthy heart will slightly increase its pace inhaling and slightly slow during exhaling. This is called Respiratory Sinus Arhythmia. If the difference between the two rates is extreme, then I suspect there is obviously something amiss. Heart rate variability has many triggers, even our thoughts can influence it. I do know that if an unqualified person in cardiology made a diagnosis with an EKG in the UK, they would get in serious trouble. The technician or nurse is meant to pass the printout to the specialist and say nothing. Perhaps the best thing to do is ask your Doctor to perform an EKG and if anything is wrong, refer you to a specialist.
I'd make an appointment to the Cardiologist. I'm sure they can do further test on you to rule out any abnormalities. I know it's tough when you are not feeling normal. I have PVC's and it's a struggle living with them. I hope this helps, I'm sorry I couldn't provide more information for you, but I'm here if you need support.
Monie