Let him know how he makes you feel, and especially what he does to makes you feel this way - things that he said that make you feel worthless, like you mentioned, for example. You might be afraid of triggering an argument that could blow up into something worse, but you really should talk about this. Relationships are about two individuals coming together, not about one person pandering to the other all the time. It's been said over and over again, but these things bear repeating: Communication is key.
The only way to know if he's happy is to ask him. Ask him what would make him happy, ask him if being with you makes him happy. But as much as you want it to be about him, it has to be about you, too. If the things that make him happy are the same things that would kill you then you need to rethink things, maybe try to work out a compromise that both of you have to make.
It could also just be that he's tired of working for the relationship and is just letting things slide. Particularly with the prospect of you moving to be with him soon, so he feels like he doesn't need to put in as much effort into spending time with you any more, since you'll be seeing each other tons.
I could go on and speculate for whole posts, so you'd better have a chat with him about this soon, before I flood the board with more (and wilder) guesses! *hugs*