Having problems already

so already im having problems in school i mean i went from prefect striaght A student to C and D student in one year. i mean school just started and already i cant concentrate. i lose it every 5 mins i cant stay on topic i try hard and when i do manage to stay on topic longer then 5 mins by the next class im tired and fall asleep. this is shit i dont know what to do im losin it im gonna go back to a sport and see if that helps but idk if it will. shit i cant even concentrate on my hw right now its to much im so jumpy right now its not funny ahhh.  is it possible to be jumpy and depressed and angry at the same time.