I have been really lucky, most of my family's pregnancy announcements I hear about through my mom or through text. I have a moment to say "WTF REALLY!?!" and then compose myself and send a nice thoughtful text, lol.
My BFF told me when we were on a double date with our hubbies. Don't get me wrong I am really, really happy for her and can't wait to be the baby's godmother. But my heart was broken too. She had hid the pregnancy from me for a couple weeks because she had been there through my IF struggles and she knew how badly I wanted a baby. That one was tough, but I learned what a good actress I was that night :/
My advice is to stay off FB. Take care of yourself and be kind to yourself. If you hear about a pregnancy announcement send your congrats and don't feel guilty about throwing a mini internal pity party. It is totally okay to feel happy for them and sad for yourself at the same time. We're only human!