What're you up to for Christmas? I can't remember how long the break is, but if you want to stay at my house sometime, you'd be welcome, of course.
You're going home for Christmas, right? It'd probably be a good idea...
Are you... okay? I haven't really seen you around. Umm, if you want to talk, you can always talk to me. But if you don't want to that's fine, I'll keep out of your way. Just checking you're alright.