Lately, since going back to school after summer i have become really lazy and unmotivated with my school work.?

i have a conditional offer with my chosen college, and have already achieved the points needed. i have completley lost any desire to do well with my work and am considering dropping an alevel and just doing 3 . im doing english literature and feel there is too much info to take in. i am interested by stuff thats going on now e.g global warming and reading novels and find it difficult to nclude all these things in my life. i am heavily involved in a certain sport and mitch school to do this sometimes. i am in my final year of doing a levels..plaese help. thanks!