You will notice the thread that runs through these replies - that the suicde seemed perfectly lucid and happy until ...
The sad fact is that anyone who is actually going to kill their pain (and that is what suicide is really about) has learned to stich a mask of 'normality' into place while they quietly and desparately reach the end behind it.
Suicide is about taking control of that mental agony that cannot be borne for one more minute - the last act of a desparate mind. It is a desire to hit back at the pain that has controlled the mind for so long - and that is why some suicides are violent - it's a final 'hitting back hard' that feels like an attractive option - if you are desparate enough.
It's very hard for the rational minds of those bereaved to understand, and anger and frustration are a very real and natural part of the grieving process.
I don't think you ever 'get over' the loss of a suicide, what you do is weave it into the fabric of your life, it's always there, but its savage impact dulls over time.
Your friend may benefit from counselling - try calling your local branch of MIND and see if they can help, or if she wants to talk to someone who understands, The Samaritans have vast experience of this sad fact of life - or she can talk to us on here - as you know, there are plenty of understanding people on here who offer comfort and support.