You seem to be aiming high, which is very positive. I think the hardest things to accomplish will be defeating depression, controlling your drug use, and getting over your ex. All of the mentioned goals are attainable, and being an intelligent being that you are, should be able to accomplish them with hard work. Learn to practice self-control to get over your drug use, and even stop hanging out with enablers until your willpower is strong enough to overcome the 'urges'. The depression is going to be difficult, but it's not a barrier. It's just a movable obstacle. That's just my two pennies. Adding structure to your day may also help with the drug habit; find a nice hobbie as well.