It's true that a lot of unrest and stress was occurring in her life (marriage on brink, financial difficulties, new baby on top of two active boys, taking diet pills, etc...) and your thoughts on her just snapping are probably very close to the truth. I certainly am more comfortable viewing this as a passionate and not a calculated act of murder.
Still, let's say you snapped like her and stabbed your sons to death...and then you come to and realize you need to save your own skin, so you slit your throat and stage all this BS and come up with this wild crazy story, etc..etc.. like Darlie did. Okay, so she's in "save my neck" mode at that point and everything she says is a lie and she's lying to cover up her crime and I GET that. It's self-preservative and we all know Darlie is into herself, first and foremost.
But....WHY no remourse at the gravesite - WHY that crazy silly string insanity? WHY the absence of any public grief even though cameras and eyes were on her constantly. If she were still in "save my neck" mode, don't you think she would be weeping and wailing to the high heavens - to look like a grieving parent if nothing else?
Do you think once she killed them in a momentary act of rage, then she truly just did not care and did not miss them and did not grieve? What is the point of keeping all of that in - whether their death is your fault or not? Does she weep alone in her cell at night? Was what she did so heinous that she has somehow managed to convince herself that her lies about that night are true - just so she can continue to live without blowing her brains out?
Where was her grief? Where is her grief? I don't know if I am making any sense, but these things confuse me greatly. This piece of me wants to know that she loved those boys and she just snapped and lost it.