So many good comments above- I do not have a lot to add. I consider myself spiritual, and tend to enjoy reading about mindfulness and many buddhist writings- many of them fall more into the mindfulness thing than religion- although yes, it is a part of the religion. You might look at Pema Chodron- she would be one whose writings I find more spiritual in nature. I do not consider myself religious persay, but I do love her writings.
I feel most connected to the spirit when I am with nature. I also feel spiritual when I do artwork.
I am not in any way trying to convert you- these are just the things that nourish my spirit. I believe with time, and a bit of trial and error that you will find what nourishes you.