Why do I miss my dad so much?

I'm a kid and my dad always has to leave every sunday and comes back every thursday or friday for work. I usually cry when he has to go, I'm not like attached to him or something but i love him very much! He loves me so much too and he is never mean to me ever! I don't believe he has every ed me and he doesn't yell at me. He hasn't for a whole year, I think the last time he yelled was in first grade, I will always be his little girl, and I'm not sure why I am so sad when he's gone. I am also sad tonight because it is saturday and he has to leave early tonight. I always text him every week to keep in touch with him. I love my whole family more than anything and I would never trade them for all the money in the world, I couldn't even spend it because I wouldn't know how. My parents always guide me in the right directions, and I appreciate them. Me and my dad are really close like best friends. Is that why? I know the only way we have money is because he works, he works A LOT and he has a very well paying job. I think I miss him is because we are so close, what do you think? Thanks for taking your time to read and answer this! p.s. my mom is super duper nice too! I love them the same!