Hey Will, I think the first step is to acknowledge this fact, as you have done - I believe our God is big enough to take our emotions and rage, so this is a good start.
When I get angry about life, I sit down and think about all the things I have in life, as well as all the important memories / events I have experienced. I then think about whether my anger is justified in light of what my life has been like up to this point.
I am not saying your anger is unjustified, or that it is wrong to be disappointed / upset about things in life, but I find that when I spend time reflecting on how my life has turned out so far, I am reminded of the times that people have been gracious to me, that I have received good things that I did not really deserve, etc.
Everyone's life is different, so you would probably have completely different experiences to me - but this is something I do, and I've found it helps, so I thought to suggest it.
It is also a good idea to talk over the issues with a trusted friend - I wish you all the best.