I am so sorry about your nephew's passing and that the anniversary is causing you pain. It sounds like you two were close. I hope you remember him in ways that help you grieve.
The year after my divorce was a long, miserable and lonely one. My ex broke up with me and my OSO ended our romantic relationship shortly afterwards. I felt very, very alone. I was devastated by two such losses in so short a time. My life as I knew it ended. I was very broken, sad and lonely.
You are broken right now, I'm sorry to say. I was. I am healing but it takes a while. It hurts so much but it is ok to be broken. Mourn your losses - they are real and need acknowledgement.
Focus on building a good co-parenting relationship with your ex. That will be very hard but, as you know, necessary. (Why is she angry with you? Is it different beyond what has already happened?)
Rely on your friends and family. They supported me through some miserable times. Get out of the house, go do things you enjoy even if you don't freakin' feel like it sometimes. This will help you make more friends, which is a good thing. Rant on here when you want to. Get counseling if you think it would be helpful. (This is still on my to do list.) And if you are a pet person and can take care of one, get a pet. The only reason I got out of bed on some days was because my dog needed me.
This first year after divorce will be one of the hardest of your life. The pain will lessen and become more manageable. You will have good days again. You will become less broken and eventually more wholly yourself. You will discover new things about yourself that you never anticipated. This is startling but a good thing. But it will not be fast or straightforward.
Now is the time just to hold on and grieve. If your experience is anything like mine, it will be all you can do anyway.