I have really struggled with this myself. We have had some truly horrible times the past few years. Last year when I had a miscarriage at the start of my 2nd trimester I was devastated to the point of questioning everything in my life, and just being bitter.
I read books (If you are a Christian, or Jewish, I highly recommend "When Bad Things Happen to Good People").
I talked to a pastor. I talked to friends. I talked to God. I talked to my husband. Hell, I was probably talking to myself at that point.
The best thing that I ever did for my heart and for my spiritual life was to admit that I did not understand it all, and could not make it make sense. That may not sound settling, but for me, it helped a lot.
I had been trying to justify everything that I knew about God and the universe and make my troubles make sense somehow within that dynamic. I felt like I couldn't understand how a God who is infinitely good, and omniscient, and omnipotent would allow things like this to happen. I'd heard the notions that "everything happens for a reason" or that "God has a plan" but no plan seemed worth the suffering I'd seen in my children, and the loss of my child. Why would God create a life only to snuff it out after it had grown a nervous system and could feel pain, and after we had grown to love it so much? It was too much to bear, and I was left feeling like either all I'd known about God was wrong, or I was being ignored/ picked-on. It was very hard to understand. But holding on to that confusion and hurt only furthered my pain.
I was forced to reevaluate what I know about my life and my faith. I finally came to the conclusion that God was NOT smiting me, and that he/she is not ignoring me either. Maybe we don't know EVERYTHING about God. We're humans, and there's more to the story than we know (The book I mentioned before started me wondering if my perceptions were off, by guiding me in a good way toward understanding the kind and gentle nature of God, and how there are possibly many things still to learn about the divine).
Since I don't know much of your specific situation, I can only share what really helped for me. I did a lot of research and opened up my mind to new possibilities for the first time, maybe ever. You may already be more open minded than I was! By doing this, I was able to find some answers that seemed to resonate with me.
I decided that maybe things just happen too. Maybe there is no REASON for it, and that all we can do is respond to it. We can grieve. We can memorialize whatever we can / need to. We can live the best we can. We can experience our spirituality however any of us see fit.
That was originally how I started letting go. I learned to slowly let go of my hurt and pain (from what felt like a spiritual betrayal to try to describe how I felt after everything that had happened). I opened up to new ideas and found some answers that I felt resonated with me. I don't want to tell you what the "right" answer is because I think it may be different for each of us. My suggestion would be to just consider that maybe letting go is a matter of admitting that maybe we don't really understand everything about the divine within the confines of one particular faith.
I know that may not be a popular opinion, so I apologize if I have upset anyone. This is just my experience and what worked for me.
HUGS
