My boyfriend died 3 weeks ago, please help?

I'm only 15 years old. My boyfriend was 16. He had stage four malenoma (skin cancer). When I met him I knew he was going to die but I didn't think this soon. A month ago he told me his cancer had spread and he had 6-12 months, it spread to his brain. He called me and told me he didn't have very long left, and then he died. I don't know what to do without him. He meant so much to me. We did have sex, so he was my first everything. I'm not a slut, he was the first guy ive ever been with and I don't put out, I'm not boy crazy either. I get good grades (honours), so don't tell me stuff like I shouldn't of done it, whatever. Anyways. I've been so angry lately. I have no one to talk to, I feel so trapped. Nobody uderstands. I can't tell my parents, they don't know about him at ALL. so that's not an option. I hate the feeling of always having something missing, I always feel like I'm forgetting something. I still check my phone to see if I have any missed calls, even though I know he can't call me. I try so hard to be happy, but then something reminds me of him and I feel so lost. I miss him, and everything about him. Sometimes being sad is so much easier because then I'll never be let down. I have nightmares if him dying and I wake up and realize hes dead all over again. I feel crazy because I don't want them to go away, because in them he's alive for that one second, so I can still see him. I'm always flipping on my friends because it seems like they don't want to talk about it, and when I do talk to them they say things that make me really angry. I don't know what to do. I'm so angry that he had to die. I release all my frustrations on the people around me. What do I do? How do I handle his death? I remember being on the phone with him when he told me his cancer spread to his brain and just sitting there forever not saying anything. I'll never forget how he sounded.