Actually at your age you should be getting around 10 hours of sleep some adolescents need even more. And just because you are sleeping it doesn't mean you are getting "good" sleep. I would suggest lengthening your sleep time by 2 hours, decrease stimulating activity at least an hour prior to bedtime, this means TV and internet. If you are still sleepy go to your doctor and ask for a polysomnogram (sleep study). Hope that helps!
You should not use look at screens prior to an hour before your bedtime. Blue light emitted most of our gadgets disrupts our sleep pattern. Dim the lights to feel drowsy