Bf problems..?

So my bf of 6 months has been acting a little weird lately, he seems really depressed or something and ive barely had the chance to talk to him bc he’s so busy with school and band, I’ve asked him why he’s acting like this and he said “ a few little things but mainly because I can’t talk to you as much anymore “ he never told me what those little things were and I’m really concerned what should I do? ( I’m 14 and he’s 15 )