Hi ChaterAlly,
Did you do something that made them go away - and how many times a day did you get them?
I believe thyroid problems can affect heart rhythm as well. The doctor may have to retest and adjust your meds. I have arrhythmias that cause the same feeling you described but mine are harmless. I hope you follow up with the doctor and get clearer answers about what's going on.
You will find many in this forum that experience these "skipped or missed" beats. In most cases they are benign and nothing more than a nuisance. They can be scary and yes they will take your breath away. I used to suffer with those. I had SVTs for some time, but thankfully they have disappeared. If you are worrind about this talk to your doctor, but like I said this is so common. Ally