In high school and completely overwhelmed, what should i do?

I remember what school was like and I had a hard time keeping up sometimes .the best way for me to concentrate was to listen to some music while working and only work on something for 15 min and then move on to the next thing for 15 min ETC.just keep doing that til you get everything done and your caught up sometimes just looking at the whole picture can be over whelming and if you do it in 15 min intervals it makes it easier .I just know it worked for me. Hope I helped