I have 12-13 hours to study per day..some days I do study but more days I waste all of my time

I have 12-13 hours to study per day…some days I do study but more days I waste all of my time…I dont have a winner’s atitude but yet have a trier’s atitude which has always succeded me in what I have achieved till now…watched and listened to tons of motivations and the great thing is that I know this is my last chance but still I am not being able to give my all why I dont know…is there a way I can maintain myself with 12 hours a day…thankyou…