I personally am not religious. That's just not how I see fit to make sense of things. I'll be the first to admit that I'm no better or worse off for it. For me, the things I don't know keep me going. I'm content with the fact that there are things I don't understand and that I may live another day and perhaps get a little bit closer... ...that I can still wake up tomorrow and see things differently. I like to question things, especially my own experiences.
Our senses and consciousness are so very fragile and fallible. It's a source of never-ending fascination for me. In my mind, the idea of a god or some metaphysical force is in some ways less amazing compared to the idea that life and the range of experiences it encompasses are somehow nothing more than the laws of nature proceeding to their natural conclusions. I like the idea of it all just being this never-ending rabbit hole of interacting forces. It leaves you with more to learn, experience, and interpret.
However, I have experienced some deep losses in my life. I have mourned the loss of several family members. By far the most difficult has been the loss of a dear friend. He was truly like a brother to me. Our families are essentially as one and remain very close to this day. I have spent years trying to make sense of it... ...just trying to find where it sits in my understanding of things. Things are better now - life is good, but I often still feel as though something is missing.
I occasionally find myself making strange connections, much as you do... ...things that to an outside observer would seem unrelated and perhaps a little crazy. To me, they're absolutely crazy and not in line with how I make sense of things. But for me, there's no conflict... ...no cognitive dissonance behind it. I know that it shouldn't be. I know that it's all in my head, but I don't mind.
I could analyze and tear these experiences apart. It's in my nature to do that. But I don't. I instead choose to take them for what they are to me and cherish the feeling. I keep them to myself. Those are mine to hold and I hold them dearly. To me, they're simply little reminders of what once was. They don't have to hold meaning for anyone but me.
Even though these people are gone, they live on as little pieces of my internalized self. It's nice to have those reminders. They bring me comfort. It can even be empowering. They live on in the back of my mind and in the corner of my eye. I carry pieces of them with me everywhere I go, so they're never too far away. That's "enough" for me.
So no, I don't think you're going crazy. It's a natural part of grieving and coping. Use these experiences as tools to progress and overcome. Just press on and take things as they come. See where it takes you...