brother died today from herion overdose?

I got a call today from someone who was close to him (his lover) all hysterical and upset telling me my brother had died. I thought it was a sick joke (this girl tells a lot of serious lies) so I called my mother. unfortunately It was the truth. im kinda in shock right now. I feel like his death didn't happen, I hoped they had the wrong body and mixed it up but I know its denial. im obviously devastated and been crying nonstop. I feel like a part of me has died. im the only one left (mom only had 2 kids) and I feel alone. I don't know how to get over this. I know it will hit full force tomorrow. but in the meantime how do I settle myself down. I don't know if all these emotions are normal. I need to compose myself cause im meeting the funeral director with my mom tomorrow and I don't wanna break down cause I wanna stay strong for her? how do I do it? im feeling so fragile right now