Boyfriend's death due to cancer?

I'm 16 years old and when I first met my boyfriend I knew he had cancer (melanoma), but 3 weeks ago he told me that the cancer spread to his brain, and he died. He was given 6-12 months, and that was at the 7 month mark. I don't know how to handle him dying. I ignore it thoughout the whole day , but at night time I don't know what to do. I cry myself asleep every night, and I don't sleep because I get really bad nightmares about him leaving, and then I wake up even more scared because then I realize he is actually gone. I miss him so much it hurts. It was a really complicated relationship to start with, because his family life, poverty, abuse and his brothers death. I don't know what to do. Im trying so hard to be happy, but I cant be happy. I feel so alone. My parents don't know about him, so they cant help. They wouldn't of liked him because he was black, and he wasnt 'rich'. So I can't talk to them, and I never would anyways. How do I deal with him not being here? My friends aren't much of a help, all they say is "awww", or change the subject. I have nobody to talk to, and nobody understands how hard it is for me. How do I deal with this? I would never kill myself, because I'm not at all suicidal, just really depressed. I want to be happy , but I can't. He was my first everything. What do I do?