What happens if i think the worse scenario very often and i feel this is deteriorating my life. how do i stop it and interact more with life?

Therapy helps: You're noticing your negative thinking here, and that's an extremely important step towards health! you can indeed learn to interrupt these thoughts (along with the detriment they present in your life). Please connect with a good psychotherapist, who can help you discover and deal with these patterns in your thinking/feeling. They don't have to dominate you, and you don't have to do it alone.

Anxiety Disorder: Anticipation of worst happening (even if it is exceedingly unlikely) is a symptom of anxiety disorder. This is a distortion of the normal fight or flight response every human is endowed with. Your brain seems to be wired for flight for any environmental stimulus, no matter how trivial. If this is so, see doctor for exam & to formulate a therapeutic plan to include counseling & medication as needed.