As for what you should be doing - stuff that might have him wondering what he's missing. (The opposite of what you seem to be doing from your last message) Instead of wondering about him and his motives/emotions - you can only control and understand your own! Get out to see friends, maybe even book a trip - a girl getaway!
At the 4/5 month mark, my work-life seemed to be in a tailspin. H was very supportive, he sent me a message after learning I hadn't got a promotion I'd been "promised", was not pursuing at all - it was like he would be OK if I moved away. (And he admits now that part of him was hoping I would, to make the separation easier to deal with). That support had me starting to think...