How can I get over his death?

It's like since my dad died I've been a different person. Since then I've been in this antisocial shell. My dad was the source of my happiness. He understood me for who I was. Since he passed I've been lost and ive been trying to find out where I fit in society. I've been trying to figure out how to become social on my own. My mom doesn't understand me like my dad did. I just don't know how to get over his death. I think I'll never be able to break out of this antisocial shell until I can learn how to get over his death. I need some serious advice