don’t worry too much. There are several conditions where you’ll experience irregular heartbeat and I don’t think they’re in any way life threatening or serious. I would think your blood pressure is low, possibly. Do you feel faint, at all?
it could be atrial fibrillation. It will make you feel under-powered and unwell, plus you’re getting that from the ms as well.
you will probably find that it settles down. The main thing is, I don’t think you’re having a heart attack or anything like that. The best thing to to do is lie down and rest.
but I’m not a doctor. You must get it checked out ASAP if it continues. Is there a hospital drop in centre you can go to? Did the helpline help at all?
main thing is, don’t worry. Rest, concentrate on your breatihing. It’ll be alright.
ps not wanting to worry anyone is not a good reason for not seeking medical advice. After all, you’re worried, don’t store it all up.