You're still very young and you have your whole life ahead of you and there are things you want to achieve, it's very understandable but go and see your doctor and get it checked out, for peace of mind if nothing else. I don't think you're going to die at the age of 18 or be in hospital.

We just lost our mum a few weeks ago and cremated her last week, she never smoke, drank, stayed up late or put a foot out of place but she still got lung cancer, saying that she lived her life to a good age and she lived it well but we all learned that even if you lead the most blameless of lives that you can still get cancer, what she did right though was when she had the cough that wouldn't go away, she went and got it checked out and that is all you can do in the end.

Don't build up things that might not be there, not easy but you have your whole life ahead of you and more than likely you have nothing to worry about, good luck and take care.

It's unlikely you have a serious condition. The symptoms you have mentioned are very common ones and could be caused by lots of things, most of them minor. Could be just some kind of tummy bug or just stress.

But you do want to find out what is causing it, if only to stop you worrying about that slight possibility it's something serious. And if it is something that needs treatment (which is still far more likely to be something like colitis than leukaemia) then the sooner it is treated the better. Seeing a doctor will reduce the chance of you dying or having to go to hospital. I really doubt either of those is likely anyway, but on the off-chance this is more serious than it sounds, seeing the doctor as soon as possible means it's more likely to be treated before it gets to the point that you would need to go to hospital.

Yeah it's been about 8 days but symptoms are ever so slightly improving. I haven't thrown up just the feeling comes and goes. 

The odds are it's nothing serious, but if it doesn't continue to improve or if the improvement is very slow, you should go and see a doctor. I'm not any kind of expert, so this is just my unqualified opinion.