Don't like myself right now...?

I'm usually a straight A+ student, popular, and know exactly what's going on in my head, with my emotions, and with the people around me but, recently, I've been feeling very distant from everyone; even my best friend who is my other half. I have lost my desire to get good grades ( even though I continue to somehow), and I'm feeling angry toward everyone. I'm 13 years, female, and in 7th grade. Why am I feeling this way? I am clinically depressed but I have never gotten this bad and it seems different. thanks for any help.