Help guys! Please.. read all!

My boyfriend of 5 months recently got depressed. Alot of the time he says don't worry about it or he will say that he won't get better. I hate it. I hate that he doesn't like himself. I try to ask what's wrong and he'll kinda go around my question. I'll say what's wrong he'll say everything. I'll say like what and he says stop. So I do stop and don't try to force him to talk about it. It's really hurting me because I'm the type of gf who loves attention. Lots of it. I don't like this because he usually gives me all the attention I need and more. It's like he's slowly pushing me away. But no matter what he goes through I will be 1000% there for him. Long story short what could I do or say to show him i love him and I'm here forever and that I'm here when he needs me? I like to write him paragraphs about how much I love him. And do simple things like that. But what would you do? And I don't wanna force him to tell me why he's sad. Like tonight we got otp and insted of talking he just said he was going to sleep. (We always gts on the phone). Thank you. Any thing would help me rn. I just want him to be happy again...😪.