How can I apologize to my dad for this?

well it seems you obviously didnt mean to hurt him ...but if you want things to be alright again say how grateful you are they let you spend some time with your friend...if you let them know how thankful you are to have nice parents they'll understand how much you love them or you can also be like "dad, thanks for letting me spend some time with my friend last night...i had to tell her something so sorry if it sounded like i didnt want you around ...love you " ..good luck!