How do I know if I’m depressed or just lazy?

So I’m a 17F still in school, and I just feel so sad, drained, and helpless all the time. This isn’t necessarily uncommon for me to feel this way, especially while in school, but recently it’s just felt different. Usually, it’s never been in the way of my school work and extracurriculars, but recently it’s been really hard to me to keep up and I feel like I’m falling behind. I keep missing school because I can’t ever muster any strength to get out of bed, and I just can’t be bothered to do any assignments anymore. I’ve lost interest in all my hobbies, and the only thing I ever want to do is just sleep, even if I’m not tired. I would consider myself a pretty lazy person in general, so that’s why I don’t know if something is wrong with me or if I am just finding excuses for myself to be lazy. I know that me missing school and not doing my work is hurting me, but I literally just cannot find any motivation to do anything about it. Please please pleaseeee give me any advice because I don’t want to make a dramatic scene if I’m not actually depressed.