Since yesterday, I have been just doing normal things like I usually do and I will suddenly get one single very rapid heart beat (like you do when someone scares/startles you and you lose your breath a little) and I can kinda feel it in my chest but there is only one, and then it will go away. Sometimes it happens about 10 times in an hour, and sometimes it doesnt happen for hours. It is kinda scary but I don t know if this is normal... does anybody know?