Boyfriends Emotions

So I’ve been w my bf 2 years. I’m 17 he’s 19. He’s SO emotional about being liked and having friends. Every time he’s sad I feel like he takes his anger out on me. He’ll be grumpy and push me away as if I’ve done something wrong. Today his friends went out and didn’t invite him and we were supposed to hang and he cancelled cause he was upset/mad. I wanted him to come over anyways cause this is the only day we’ll see each other this week but he said no and when I tried to talk to him about the way he was feeling he told me not to start w him and that he’s gonna say something he’ll regret. I love my bf but the way he acts when he’s sad scares me. What do I do? I hate feeling like I have to worry abt him all the time :(