Confused

Ok for some time now there have been some certain people in my life that have been pretty much non-existent that where a big part of my life when I was pregnant and to the present. Those people (no names mentioned) have just pretty much stop all communication and for what? I have no clue why that it has stopped and it's really hurtful. If I had done something or said something I would really hope that they would feel like they could talk to me about it. It's actually pretty sad that this has happened I am wondering if maybe it should have always been like this or if life has just gotten in the way. I am really confused?