not to tell anybody that I'm pregnant unless necessary!!!

I have this almighty urge that if we are pregnant again not to tell anybody IRL (ie friends and family) unless a) they ask once its obvious or work it out for themselves b) or it is necessary because we need support for the family (eg so sick need someone to help with kids or whatever).

I don't really know my true reasons behind this as to whether its because I'm feeling very used by people lately and feel they won't be truly happy for us anyway, don't want to cop the flack and associated comments about having more or I just want something special for our family to share for as long as possible. I think its a mixture of all of these things in reality but was just interested on others opinions.