Awe, that's sweet! Once when my middle son was about 4 he saw me crying, I forget what for. But ran and got his story book opened it up and started reading it to me (by the pictures he couldn't read words yet), all the while he was patting me on my leg. I cried even more because he was trying to comfort me, when he finished his reading he kissed me on my cheek and said, "it's gonna be ok", you want some juice?
All I could is laugh at that point. A story, some juice, a pat on the leg and kiss that's all it took in his little mind to make mommy happy again. It worked because I started laughing.
This probably was the first time in his little life that your little man realized that mommies get sad too. Give him a kiss for me, it brought back memories of my kids when they were little.
nj