Hi and welcome to HCM.
You are in the middle of puberty
and your hormone levels are raised and it is normal to do what you do and have increased sexuall desire. But sometimes it can lead to addiction as you said and this aint bad until it cause problems in everyday jobs and duties. YOu should seek for psychologic help and I am sure it can make you feel better and pleased. It is hard to focus on studying in this age but you have to think on your future and take responsibility. Wish you good health.