You don't have to take drugs to be a junky. Take care of yourself and go outside.
Accomplish something, it feels really good. Even just clean your room.
Don't chase girls. Difficult girls stay difficult. Focus on the ones that aren't hard work.
Be independent. Make a list of stuff you want to do and then go do it. You don't need a friend to go with you just go by yourself if you have to. Rock climbing, mma, gym, fun stuff but whatever you're into. Just lean towards stuff with a social element if that's something you need to work on. It was for me.
Buy property. Don't get a credit card. Don't get in debt (unless its to buy property).
Friends are important. Have people in your life you can be honest with and feel comfortable around.
If you hate your job find a new one. Just put in an hour a day towards applying for stuff and you'll find something. This applies to most stuff in your life you want to change.
Get your diet under control. Sugar and carbs might not be messing you up now but when you hit 30 a lot of people with bad diets start putting on loads of weight and getting health problems.
Mental health stuff is important, get help if you need to. CBT is really good.