Am I depressed?

Ive been sad almost everyday for 2 years and this whole time i thought it was because of school and my grades. But now that i passed all my exams and school is about to end, i still feel sad and hopeless for no reason at all. I feel like i should be overjoyed about it, but i feel nothing. I don’t even want to get out of my bed or eat anything. It’s just strange because i don’t have anything to worry about and yet i still feel like this.