I feel very depressed and my midterm exams is after a week and i can't study at all, I need help?

i'm 22 male. i feel like this approximatly for 4 months and trying to hide it from everybody and i ended up smoking weed and i became alcoholic and i started to don't care about my studies inspite of having high grades (my gpa 3.1) and this is my final year.any help would be very appreciated (sorry about the messed up spelling i'm not a native speaker)