hey there lovely. You are grieving, and it is normal and natural that you would feel angry, sad, confused etc. "why me?" is a part of the grieving process, and there is nothing wrong with your feelings. Feelings just are, they do not merit judgement. I can see how you could have thought some of the comments on here were judgemental (I am NOT saying they were) just I can see how, if you are used to juudging the morality and "rightness" of feelings, you could think that was were they were coming from.
I can see that because I've been right where you are now. It is a dark time, but it DOES get better (then it gets a bit worse, then better, etc). You know life is up and down.
vent away. Dark, sad feelings can be scary, if you are worried they are too much to handle, get some outside support, a GP a therapist, in fact get some outside support anyway, there are no medals for doing this alone.
If you aren't worried that this may be turning into a clinical depression then I would suggest that before you get out the gratitude lists and attempt to "turn that frown upside down", you have 1 or more darn good rants, on paper helped me, but also hearing it out loud, shouted out on the top of a mountain into the wind if neccessary and have a few good wallows in the grief, get warm and cosy, with a box of tissues and feel sad for all the sad things that have happened, acknowledge the fears you have about the future, the dreams that will need to be realised in different ways.
Understand that sometimes this will feel like too much, but believe me, you have survived the chaos of living with your other half, and therefore you will survive emerging from that relationship. let yourself feel whatever you feel and know that this is a process and that whatever place you are in, right now, is normal and not permanent.