The last voicemail I left him was just, like, Hey, sorry I've been calling a lot but this is a long time for me not to hear from you, even for you, and you know I'm a worrier, so please just call me and let me know everything's ok, yada yada...
He knows that I really do worry when I don't hear from him, so if this is on purpose or something, it's really, really mean.