Could Me Using My Computer ( Up To 5-6 Hours) Be Hurting My Grades ?

Definitely. There are countless ways doing less computer can help improve ur grades. Heres just some: Less computer gives you so much less distraction from studying for tests and stuff(#1 reason). It will keep your mind clear for learning instead of cramming your brain with computer. Terrible habit thats hard to break will never happen if you don't do as much computer and so on.