Dear friend

What you experience is GAD(Generalized Anxiety Disorder) and from what you said about it being everyday then it's chronic. Good that you have identified your symptoms and you are able to express it clearly. being young you need to tell this to your parents. they can take you to a therapist who will be able to talk you thru it. well if you want to try out some self-help tools you can try deep breathing, meditation, EFT, Progressive muscle relaxation techniques. you can find video tutorials in internet and youtube.

if these don't work then you need medication. but now since you are facing your exams you can meet your GP who can prescribe something to help you relax. once you are done with the exams, approach a therapist who can help you thru this. Good luck and lots of hugs