I think everyone has a right to know they have a kid on the way. So yes u should tell him, but hey if u are not comfortable telling him face-to-face, then just call him or write him a letter. But face to face is much better coz u can see his reactions.
Also, I think at 14, u are not financially independent, so u need to know how u r gonna support ur baby during pregnancy and after giving birth. There are alot of organizations that help teen mothers, so be sure to check ur local phone book and ask around.
And sweetie, tell ur parents, it's only fair that they know they have a grandchild on the way, and they can help u. If they freaked out, give it time, after the shock, they will try to best to love u more and help u out. I am sure.

good luck