"Part of me thinks this is bothering so much because I'm so busy with school and work"
It seems like that to me; perhaps anyway, you are just getting caught up in your own anxiety and he doesn't know how to deal with it.
Try to just stay with your breath, or focus on something positive; stay in the moment and see what happens when you see him. You need to talk with him about your perception of his being immature, but you should do that in person. It will be a tricky one.
I have to sign off now. Good luck.
Love,
Ruby