Lost my mum and feel numb

I lost my mum 3 weeks ago.  She had stage 4 cancer but was managing it with medicine well.  Then all of a sudden she caught a nasty infection after Christmas.  She got progressively more ill but none of us expected this.  I don't know if I was just naive but I just always assumed she'd pull through. She was the strongest person I know and I know she kept a lot of the pain she was in away from me.  The 4 days she was in hospital were honestly the worst of my life and something I will never forget.

My husband and family say I'm coping remarkably well but that's because I almost still don't believe it.  I have cried and I do still have moments but nothing of what I would have expected knowing how close we were.  We were like best friends and spoke on the phone everyday.  I find 5pm the hardest time of day as this is when we spoke.  I just kind of go quiet and a bit grumpy.  

I don't know why I'm posting I guess I just feel lost and so guilty with have young girls.  The oldest can sense when I'm having difficulty and will comment (why are you sad? Etc).  I kind of feel like how is my life going to go on without her.  (Not in a suicidal way). Just in a completely lost way.  I can't imagine her no longer in my life.