So many things I want to say as I read your post! I'll keep it simple and say "me too". My story is a bit different but boils down in a similar way to simply not feeling like I'm called to have children. I too believe that it's a HUGE undertaking to become a mother and am in complete support of those womenwho are called to it, (yes, go for it!!) but there's no need for you or me to push ourselves to become mothers when we don't have the burning desire. I too love some children and love more and more my role as auntie to my nieces and nephews.
I'm sorry that people have given you a hard time about this. For some reason I haven't had this experience but have maybe given myself a hard time about it or questioned my decisions a lot when I read articles and such.
Anyway, great subject and one that helps give women permission to make their own choices and know that other women will support them.