Hey girl I don't think you are rambling or being immature at all, this is real life stuff and it hurts!! My 2 cents for what it's worth, I am sure with any relationship there is a mourning period sometimes it hits right away, or it could take days, weeks, months before it hits. Something can trigger it or it may just hit out of frustration. Maybe he is finally dealing with the fact it's over and he has made his choice to work on his M and is just working through it.
IMHO you taking the bubbly light approach is probably best, keep reminding him he mad the right choice...