Keeping TTC on the down low...

My husband and I are trying to conceive, and are keeping it between us until we have some news to announce.

However, my friends and family are being somewhat pushy on the issue; they comment that I'm not drinking, insist I must be pregnant, and wink at one another.

I'm not sure how to respond. I don't want to be public about trying (after all it could be a very long time before we succeed, and I'm not sure I want the extra pressure!) and I don't want to lie and make up and excuses...

Any advice on how to handle the inquires?