Let me first just tell you again how sorry I am. Not that it will help and I'm sure you have heard it enough times to irritate you rather than take strength from it.
This piece is a very personal write and one I felt was difficult to read. All the negative emotions one person can feel are here: anger, frustration, sorrow etc and a real feeling of disconnection with reality.
Commenting on the poem from a technical point almost seems crass, so all I will say is that it is well written and I love your scattering of rhyme throughout - it simply reinforces the emotion at points.
I do hope you feel better soon. But know that while you are writing and letting it all out and not letting it consume you inside, things will start getting more positive soon.
as Ben says, this is a very personal write for you to pose. Often the process it a cathartic one and helps one move on somewhat.
I remember when I lost my father - I was 14 and actually felt relieved. It is a long story and I have written about it in some of my darker writes.
I like how your poems follows your trying to come to terms with your loss, whilst trying to be strong for others. The emotions are acute and at times it must feel like no one understands.
Time is a healer, if not a healer it allows for space to form between the pain and the day to day life that just carries on regardless.