Ive conviced my self i either have cancer or someother illness ... please help?

Ask yourself one question: What happens if I live to be 100 with nothing more than a cold or flu...where would all this constant worrying have gotten me." Your answer: Nowhere. Stop thinking, and start living. You are ruining your life at the potential of it being nothing at all.

Ask a Doctor.

Doesn't matter how much you convince yourself. You don't have cancer.

Go to the doctor first 😊

Seems your problem is imagination and overreaction.

Then see a doctor for an actual diagnosis.
Without that,all you have is hypochondria.

Do you have cause or genuine concern for any reason ? A lump, a bump, a funny looking mole ?
Cancer comes in all forms, sizes, different areas you know so while your concern could be genuine, it's probably just a fear of some sort , maybe a relative close to you was lost by this horrible disease ? I think In some way we all fear this one day as we've seen the worst of what it can do, but it's also been cured by the day and more and more research is helping.
The only real way to be sure of anything is too seek the advice of your doctor who can talk through your concerns and help find a way forward or you...
Good luck.

Stop using Google to self-diagnose.

If you are in pain or showing strange symptoms, I would schedule an apt Monday. If pain is unbearable, go ahead and head to the ER.