Told my Mum I'm pregnant, not a good response

Flora • Gracie Amelia Mary, due 21st Aug 2016, arrived 23rd Aug 2016 💖👶🏼
So my partner and I have been together 6 years, we're engaged, have a mortgage and both have full time jobs. 
We told our parents that I'm pregnant this weekend, his mum and dad were absolutely thrilled and my dad was over the moon, which was amazing! 
My Mum however, didn't even stand up, didn't say congratulations etc and kept coming out with little digs like "did you do this because you can't afford to get married, so you thought you'd do the next best thing?" And other things. 
This was on Sunday and I haven't heard from her since. I'm SO pissed off with her.  my dad and sister are ignoring her (they all live together) and my sister has said how ashamed she is of her behaviour. 
This is their first grandchild and I just want my Mum to apologise for how she acted but I don't think she will. Am I wrong for being pissed off?