How come some people don't let you mourn over death of loved one?

Everyone has been telling me I need to move forward and once a person is dead they're dead.
I mom unexpectedly passed away and I'm devastated. I had to go back to work after I took a week off because I'm needed and they didn't let me take another week off when I wanted to. My moms memorial is next Saturday. I don't wanna do ANYTHING anymore. People have been inviting me to places but I've declined. My aunt askes if I wanted to go to the casino but I declined that too. She told me, "Look I know you're sadden about the loss of your mother. We all are but she wouldn't want you to be all sad and depressed and miss out on life. A evening/night out at the casino can cheer you up. Come on. Get dressed and lets go. I'm not taking no for an answer. My cousins were working that day and my male cousin was him and all the guys were there. Why didn't she ask him if he wanted to go? She's always asking ME not them. She prefers me over her other nieces. Anyways why can't people understand that I need to mourn some more? My dad said it's heartbreaking but we still gotta move forward and laying around sobbing won't do any good.

My family is insensitive.