Oh it's too bad about your dad and your friends' reactions. I believe you feel what you feel, at any age, and it should be taken seriously. Depression is still a taboo subject to many. I would love for more people to be honest about it, get it out there, talk about it, understand it, deal with it... I hope your doctor visit will be helpful.
as for you best friend, it's good you guys will be talking tomorrow. Clear the air. Good luck with that!