I feel like im going to shit.

Im 16 years old and i just feel im going down the wrong path and its like why try in life if everything is going to go to shit again, im failing in school really bad, i got little friends but those i do i cherrish and am grateful for, but i dont know what im doing in life, i feel like theres nothing to be happy about sometimes, but its funny cause 4 weeks prior to this i was doing great with life, exceeding expectations if you will, i dont know why i stopped but i did and now i lay down every day not having a hope in anyway to cherrish moments are try to try, i just want some advice to see if anyone knows how to help