The best way you can take control is to pick up the phone and make appointments with both your primary care doctor and a mental health counselor. When there is a change in someone like this, I always advise a visit to the medical doctor first to make sure that the symptoms are not a consequence of a medical issue.
If you are physically okay, the next step is to continue to take control of your life by seeing a mental health counselor who can help you assess what is happening psychologically and give you recommendations for how to get out of the basement and back into life.
No one can get you the help you need but you. I hope you will follow this advice immediately. The longer you wait, the chances are whatever is going on will only get more challenging. You deserve to reclaim your life and to enjoy your teen years.
I wish you well.