My dad won't believe I have friends

So, I am a middle school girl and I'm moving across the country this summer, July 11th. These two girls are my best friends, and have been since 3rd or 4th grade. They're like my sisters, they're a part of me. Every time I talk about them, my dad makes a comment, like "Just admit it, you don't have any friends.". One of them is for some reason afraid of my dad and the other is afraid of my dog, so they've never been to my house. I have gone to the movies with them several times, however. I normally wouldn't care, but my dad just pretending they aren't a part of my life when they mean so much to me hurts. They're one of the only reasons I don't want to move, I don't know how to deal with being away from them. I hate being alone, I'm not good in social situations, and being the odd one out is nerve wrecking. I've always had my friends, through new school years and tough situations. But, I won't have them now. I'll be alone. I've never been truly alone, and I'm terrified of it. That's why my dad pretending they don't exist makes me so upset. How do I make him realize I'm not just making them up? Every time I say I'm upset because I'm leaving them, "Good thing you don't have friends." or, "Stop pretending you have friends." My brother does this too, and it's even more frustrating as I already have my own problems. It's making my blood boil just typing this. A little help here? Thanks in advance for any advice.