How do I stop being sad?

I have an addiction to the internet and I have an eating problem. I also never do my schoolwork, and go on the internet researching questions. When I was in seventh grade and got in trouble at school, I cried so loud I cried so much worse than a baby, and when I was in sixth grade and got an office referral, I cried so hard my parents had to come and everyone heard me crying. I now either feel a bit of happiness and then regret from procrastinating or I just eat all day. I don't know why I was like this and why I'm like this cause I have a great family and I got exposed to an iPod and played it for hours and hours straight when I was 5 but I played with it for so long even though kids exposed to electronics at the same age would play for 2 hours a day. I sit on my laptop for like 16 hours still and tried solutions but they won't solve the problem. I also bite toys all day and I can't stop. This is my paragraph before my dad gets upset at me.