That could be anxiety and maybe a little bit of depression. I remember when i started first having panic attacks i thought i was dying but you don't .you just feel like your going too i don't know why it happens but it does. . . (if you worry so much about that one thing then you start to believe it )But just to make sure everything is ok go to the dr. and have them check some things out that way when you know nothing is wrong you won't have anything to worry about. Because theres "anxiety" thinking and then theres "our" thinking i know it sounds weird but anxiety and fear can make you feel and think weird things. keep in touch let me know how your doing.
Its really hard to say. You need to tell your parents how you feel and then get into the doctors. Have them run tests just to be sure there is nothing medical going on and then take things from there. Has anything traumatic or stressful happened recently that could be making you feel this way. Please talk to them and keep us updated