Whys he acting this way?

So me and my bf have been together 9 months as of the 13 and we don't keep secrets at all but lately he's been acting odd. he's always working (I know he there cause of his co-workers) I ask him what on his mind and he says it for him to figure out ans that hell tell me on feb 1st I don't know what to do and I'm scared he's gonna wanna end it