OMG Of course you're in shock and been through so much already! Glad to hear a bit of humour creeping through which is a great sign so keep that atittude going
I don't believe for a moment any Dr can give anyone a time line on life,no one knows and you'll read enough "miracle stories" on here as proof of that. You have a huge range of chemo drugs to choose and of course herceptin so I think it was very foolish of your onc to give you this devastating news so early in your treatment.
I know you'll get lots of advice from people here in a similar situation to you who know far more than I that will give you hope,confidence and determination to face the future and prove your Onc wrong. Your pic of the babies is lovely,really cute and they alone give you everything to fight for and ensure you do beat this.
My very best wishes to you as you begin your treatments and please keep us posted.