A confidentiality agreement and a non-disclosure agreement are essentially the same thing. And absolutely you need a lawyer to draft this document. If your idea is good you want to have iron-clad protection BEFORE you tell ANYONE and that can only be complished by an attorney who has experience drafting these documents. If you try to go out on the cheap you may lose much down the line. If you call me I may be able to advise you further.
This post is not meant to: 1) contain my signature; 2) contain legal advice; 3) create an attorney/client relationship; or 4) guarantee confidentiality.