Man needs space

So my long distance bf has been really stressed out lately about his family, and work and all he's been saying is that he's really stressed and needs some space.  But he hasn't spoken to me in over a week. And when he started to shut down he never told me so I thought I did something wrong. I gave him space (which was the hardest thing to do) but I feel like we're drifting apart and I can't even get him on the phone to talk about it. He keeps ignoring my messages. And I don't know what do to. Has this happened to anyone before? What did you do?