My hands are shaking. i can still carry a glass full of water, without spilling it. so its not hardly shaking but still, can i be a doctor?

Shaking: Of course you can still be a doctor. You can always go to specialties not requiring use of hands in very special procedures like surger or any specialty that involves some kind of surgery like ENT, ophthalmology, OB/Gyne.

Probably but...: You probably suffer from benign essential tremor. Sometimes medications can reduce your tremor. You probably can't become a surgeon but many fields of medicine do not require steady hands. However, during medical school & internship you'll be asked to draw blood and start IV's, so the question is if your hands are steady enough to do this. Consult a neurologist for possible treatment & prognosis.