He should be tasking you and you should be 'reporting' your progress and results both by mail and on the phone.

I'm a fan of keeping a dominating "presence" in absentia.

As far as feeling empty and worthless, do the things you know he would ask of you, that make you feel full and valuable, regardless of his ability to directly monitor you. I have no doubt he expects to return to a "full-value" submissive.