Ok what do u do if u tried to talk to someone?

ok so the other day i tried to talk to my teacher and eres what happened so he we were talking about yahoo answers of course and he asked what i had asked on here and it was about the thoughts of death i was having and i wanted to tell him but im scared it will ruin everything he wanted me to tell him but all i could say was just thoughts and he said he cared and he saw me as his own kids which is comforting which makes it seem like it would be easy for me to tell him but i just cant so iv been keeping it inside and now i feel trapped i dont know what to do i already tried to tell the teacher im close to should i try again or just hope these feeling will go away?